IT-Glossary 

The unlimited digitization and global networking entails a variety of new terms that we often can no longer avoid. In our glossary you will therefore find simple explanations of the most relevant terms relating to IT and technology. 

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3rd party generally describes a third party involved in something alongside two other parties. The term 3rd party is often used in the EDP or IT sector. If a device is classified as 3rd party, then it is a device that is produced and offered by third-party manufacturers (external manufacturers). Accordingly, 3rd party companies focus on the production of additional services or components, such as spare parts for products and product families. In addition, telecommunications manufacturers commission so-called third-party manufacturers with the production of certain components such as power supplies, memories and other accessories because they do not cover these in their own production. 3rd party products are 100% compatible with original devices and are a significantly cheaper and often more an attractive alternative to the original items. 

4in6 describes the transport of IPv4 data packages within an IPv6 environment. 6in4 describes the reverse variant, in which an IPv6 data package traverses an IPv4 environment. 4in6 or also 6in4 requires a dual stack router at the end points - the start and end point of the data transfer. Dual stack means that the router supports parallel operation of both protocols. This means that at the starting point, the dual stack router, the IPv4 data package can be packed with an IPv6 envelope. Then, the data package traverses the extended address space through so-called “tunnels”. Before the package subsequently re-enters an IPv4 environment, the IPv6 envelope is removed again in a dual stack router at the end point. An IPv6 data package also goes through the same process, only in reverse, in an IPv4 environment. 

In access control, different resources (e.g. files) are monitored. Access to these resources is either permitted or prohibited. Access control ensures that only certain persons or groups of persons can access the resources. Access control ensures that files are kept secure and confidential and protected from access by unauthorised third parties. There are logical and physical access controls. Logical Access Controls restrict access in computer networks and files. Physical access controls are used to protect buildings, IT machines and rooms, for example. 

The access network evolved from the telephone network. A few years ago, the telephone required a copper pair that was connected to an exchange. An exchange is a node that is located in a communications network. This technology required a lot of exchanges. In many countries, the connection density was very high, so that it was necessary to switch to controlling network elements. Colloquially, these controlling network elements are called access nodes and the exchanges are called service nodes. Today, the access network includes not only telephony, but also DSL technology, VDSL, mobile networks and the cable television network, which is also known colloquially as the broadband network. 

An access point or wireless accesspoint is a comparatively small and connecting network device and serves as an interface for wireless communication in offices or companies. An access point, often referred to as an AP, not only looks like a router, but works almost exactly like one. A local area network can be set up with a WLAN access point (WiFi AP). If the WiFi AP is connected to a router, switch or hub via an Ethernet cable, it can send out a WiFi signal and supply areas that were previously not or poorly supplied with WiFi. 

An Active Directory is a directory service operated by Microsoft. This directory service is used to manage IT systems such as printers, computers and users. Microsoft offers the Active Directory in its product family for desktop applications, the Windows Server, Exchange, Sharepoint and many more. Since Windows Server 2008, the Active Directory service consists of five roles with one main component. The main component is called Active Directory Domain Services (ADDS). The Active Directory is used to manage users and computers more easily. Information about users and computers is stored in a directory. Without such a directory, each user in a company would have to enter a user name and password for each application, and the administrators would have to assign each user to each individual application, etc. 

Adapters are devices that create compatibility between sockets, plugs and cables that have different connections and thus make it possible to connect them with each other. With a gigabit adapter, for example, it is possible for a computer-capable terminal to be connected to an Rj45 Ethernet port via the USB connection. There are passive and active adapters. With a passive adapter, the connection between the devices is established via the pure transmitted signal, which is not changed. The active adapter, on the other hand, changes the signal, for example by changing the voltage. For the conversion of these signals by the adapter, it is equipped with additional components. These in turn must be supplied with power. 

The abbreviation API stands for Application Programming Interface and is a collection of commands, protocols, functions and objects. Programmers can use APIs to allow a software or web application to interact or communicate with a third-party system. Application Programming Interfaces are often used in today's web services to enable users to connect their systems to certain online services. A detailed documentation of the functions and parameters belongs to each interface. 

The Application Layer Gateway (abbreviated ALG) forms the “last resort” of a multi-level security control, before any external content is allowed to cross the border to a shielded network. Therefore all incoming or outgoing data streams are each assigned to individual control programmes ,so-called security proxies. The security proxies briefly interrupt, analyse and send forward the content to an available Port or reject them. The data traffic is handled via a comparatively small number of released Ports. The network's security is increased by the fact that few transitions have to be kept open. 

According to the APT definition, Advanced Persistent Threat is a targeted cyber attack which, in contrast to other types of attack, often pursues specific espionage or sabotage goals and relies on sufficient financial support. An APT attack is not only complex and effective, but also requires technical sophistication on the part of the attacker. Due to technological advances, more and more hostile organizations are trying to gain access to defense, financial and other sensitive information of governments and companies, but also authorities and individuals. The multi-stage attack, which lasts over a longer period of time, constantly confronts IT with new challenges. The still most effective APT protection is an intelligent security measure, which also includes an end-to-end strategy. 

Autonomous Systems (AS) are large networks. In their entirety the autonomous systems form the Internet. A large network or group of networks must have a uniform routing policy in order to be called an autonomous system. Every device that uses the internet is connected to an AS. At the same time, the network of routers and networks is usually under the control of a single large organisation. This organisation can be a large company or a university for example. 

The Adaptive Security Appliance (ASA) software is a proven and widely used security solution. The well-known firewall from Cisco enables IT managers or other users within their own company network or data center to securely and reliably access data and network resources. The ASA firewall based on Linux forms the core operating system of the whole Cisco ASA family. Nevertheless, the ASA software can also be integrated into other security technologies and thus offers optimal protection against threats and attacks. The product line of the Cisco Adaptive Security Appliances comprises different series, one of which is the ASA 5500 series. 

Since 1988, the asynchronous transfer mode (ATM) has been used to transport large amounts of data over telephone lines. The transmission takes place at high speed. That’s why ATMs are often used in high-performance networks with very high transmission rates. The rapid transmission is achieved by splitting the data, regardless of size and type, into small packets. The size of the split packets is 53 bytes each. 48 bytes of a packet are available for the actual information. The remaining 5 bytes are necessary for the transport to the desired destination and the reassembly there. 

The English term backbone implies the core area of a network, which connects smaller sub-networks with one another. Since the data rates of all end users are bundled in a backbone network, particularly high data transmission rates are required, which are usually implemented via fiber optic lines. A backbone router connects separate systems within this network and has very strong processing capability and large storage space. A backbone or core switch is also part of a backbone and serves as a gateway for a wide area network or the internet. Also the core switch needs to have a very high capacity to handle the load sent to it. 

Bandwidth is a key figure in signal processing and is used in various areas of computer science and physics to describe the frequency range. In the area of IT hardware, this term is often used as a synonym for the data transfer rate. Network bandwidth describes the ability of a network communications link to carry a maximum amount of data from one point to another over a network or the internet. The more bandwidth a data connection has, the more data can be sent and received. 

The Business Communication Manager (BCM) from Nortel / Avaya, for example, is ideal for small and medium-sized companies to operate future-oriented IP telephony for up to 250 people. The Business Communication Manager has numerous solutions for companies such as telephony, processing of messages, IP routing and the functionality as a firewall. The BCM can even be used as a complete multimedia call center. Thanks to the intelligent contact function, people can connect with each other within a short period of time. The BCM is the perfect solution to combine IP telephony and numerous other functions in one device. 

BGP is the Border Gateway Protocol, which is also known as the routing protocol of the internet. The protocol is used for the information exchange between autonomous systems. Through the BGP all paths for the transport of data packages are constantly adapted. If routes fail, the BGP provides a new route as quickly as possible. Regardless of this, the Border Gateway Protocol aims to permanently optimise all possible routes and reduce all time delays to a minimum. 

Bit stands for "binary digit" and is the smallest binary information unit in the computer environment. It is the basis for all larger data units in digital technology and can have the binary value 1 or 0. Binary numbers represent exactly two states: 1 for "on/true" and 0 for "off/false". Computers use these binary numbers to communicate. We primarily encounter bits in data consumption and transmission speeds of internet, telephone or streaming services. The bit rate shows how many bits, i.e. data units, are transmitted per second. There are different bit multiples, e.g. the kilobit, the megabit and also the gigabit, for displaying data units and amounts during transmission and storage. 

Bulk is an English word meaning "mass". In IT, bulk goods therefore refer to a product such as a device or software that is sold in bulk. However, the packaging, manuals and other extras are missing (in most cases). Hardware, for example, is often packed in a non-static bag and contains at most a driver CD. Software CDs, for example, lack the outer packaging and the manual in printed form. In addition, bulk goods often lack manufacturer support. In contrast to retail, bulk goods often lack the usual labels and the cardboard packaging is usually not as extensive as one is used to. Bulk goods in the form of multi-packs are also characterised by the fact that manufacturers do not package individual items separately but sell them in collections of 10. The advantage of bulk goods is the lower purchase price compared to the "normal" sales versions. If the end customer does not need manuals, outer packaging, etc., this is a favourable alternative. 

In computer technology, a byte is the smallest addressable storage unit. A byte consists of eight bits put together. By combining eight bits, 256 different states (0 or 1) can be represented in one byte. This makes it possible to encode numbers or letters in a byte and display them in computer systems. If the memory units continue to grow and more bytes are added to a byte, 1000 bytes result in a kilobyte, as the next largest memory unit. In most computer systems today, memory size is specified in kilobytes, megabytes, or gigabytes. 

Small and large companies have long recognised that it is important to serve and advise (potential) customers on the phone or by e-mail. Therefore, more and more companies use call or contact centres for this task. Call and contact centres need a person who manages staff, organises and controls processes, acquires customers and is familiar with controlling. It is also important to know the legal basis for direct marketing and the technical requirements for a call or contact centre. The call or contact centre manager takes care of all these diverse tasks. 

One of the oldest interface technologies on the internet is the CGI (Common Gateway Interface). It is often still used as an interface between different web servers for standardized data exchange. If an entry is made on a website, it is converted in order to be transmitted. This input is processed in the CGI via the CGI script. The program then transmits the data via standardized CGI interfaces to the server, which reproduces the data again in HTML. The advantage of CGI is that the CGI script can be written in different programming languages. The Common Gateway Interface is flexible and ensures that web server and script can communicate with each other. 

Client management systems, also known as client lifecycle management, are modern systems that are used for the central administration of the entire infrastructure. The client management takes into account all aspects of IT, such as the software used, the current status, the functionality and possible weak points of all devices in the network. The range of client management software is diverse and tailored to different company structures and focal points. But all client management solutions have one thing in common: they reduce the administrative effort for the IT department and help to maintain the level of performance while increasing productivity. 

Client-server technology ensures that tasks and services run in an orderly manner in a network. Computer programmes take care of the distribution of tasks. A distinction is made between clients and servers. The client is a computer program (or device) that runs on the device of the target computer and communicates with the server. The server is a device or program that waits for a request from the client to then execute a specific request from the client. For example, when a website URL is called up in the browser, the client communicates with the web server, sends it a request and, if successful, receives a response from the server and thus the data of the requested website. The requested website is then displayed on the client PC. 

Cloud networking is the term used to describe an infrastructure in which third-party providers make certain resources and network functionalities available via the so-called cloud platform. Network management, data connection and control are shifted to cloud services. Network resources include virtual routers, firewalls and network management software. Users and internal and external computing resources access the network to communicate with each other. Cloud networking allows management devices to be reduced to a minimum, thus lowering costs. In addition, the external service providers are responsible for managing and protecting the network. 

With cloud telephony it is no longer necessary to use conventional telephone systems. Instead, cloud telephony uses the internet-based voice communication service Voice over IP (VoIP). This is a software-based solution in which all functionalities that would otherwise be the responsibility of telephone systems are located in the data centre of the external hoster. There is no need for cumbersome cabling and (sometimes huge) telephone systems. The end customers thus use the internet to make phone calls. Telephony can take place either via the PC, the smartphone or via IP telephone. 

Conferencing systems are a form of electronic messaging. Regardless of the device or location, real-time communication is possible. Depending on what is to be exchanged, different forms can be defined. The text-based conferencing systems aimed at exchanging text messages, the audio conferencing systems designed for verbal communication as well as the video conferencing systems. Video-based conference systems enable so-called face-to-face meetings and are now one of the most frequently used forms of corporate communication. 

In computer science, controllers are electronic components that control various pro-cesses. Controllers support the central processing unit CPU. If these components consist of an integrated circuit, they are termed microcontrollers. Among other things, controllers are responsible for commands entered via the keyboard or access to storage media such as the hard drive. These control units are also often called adapters. These include, for example, network adapters such as WLAN controllers that connect the computer to a network. A graphics controller, for example, is re-sponsible for connecting the computer and display device with one another. 

CPU means "Central Processing Unit", which is the main processor, the "heart" of the computer. The central processing unit interprets and executes most of the com-puter commands. These instructions include arithmetic and logical operations. The CPU then forwards these commands to other units (e.g. other computer chips). It is located on a base that is attached to the mainboard. Depending on the task that the CPU has to process, it heats up very strongly. Therefore, the processor has to be cooled by a fan. The central processor unit carries out mathematical calculations and logical operations in the so-called binary system with the digits 0 and 1. 

Cybercrime is defined as a crime that targets computer systems and networks. Behind these crimes are often individuals or organizations made up of cyber criminals or hackers. The list of types of cybercrime is long and includes theft of financial or other sensitive data in addition to e-mail, internet or identity fraud. The darknet cybercrime is therefore divided into two main categories - criminal activities targeting computers/networks and criminal activities using computers/networks to commit other crimes. In order to report cybercrime, those affected have appropriate contact points of the police forces of the federal states and the federal government. 

A data center is a real location consisting of a (large) network of computers or storage resources. This includes routers and computers that act as servers. A data center normally stores large amounts of data and applications. Data centers are mostly used by companies that run their web presences, online stores, cloud applications, etc. from there. The operators of the data centers must ensure that the sites or services work around-the-clock. The entire IT infrastructure runs from a data center. Either the company itself operates a data center or it uses the services of external data center providers. 

Data literacy is a fundamental skill in dealing with data and using it in a planned and appropriate manner. For the further interpretation and presentation of the data, various skills, such as math, programming and statistics, are responsible. The more data that has to be processed and evaluated, the greater the amount of data. In this context one speaks of big data. Data literacy is one of the most important building blocks for digital transformation. People such as data specialists, data scientists and data analysts have the necessary data literacy to handle (large) data properly. 

Data Loss Prevention (DLP) is a strategy that is applied to both hardware and software in order to protect sensitive data and critical information or to prevent their unwanted leakage. As part of information security, data loss prevention monitors all data flows on removable data carriers, networks, e-mail, on mobile devices, etc. Even employ-ees who contribute to the outflow of company data through incorrect behavior, be it willful or accidental, are taken into account with DLP solutions. 

Data security generally includes all technical issues that guarantee the protection of the data. Data security as well as data protection and IT security are part of the in-formation security sector. The aim of data security is to guarantee the confidentiality, availability and integrity of the data, regardless of their type. Confidentiality implies that data can only be viewed by those who have the rights or are authorized to do so. Availability ensures that the relevant data is always available to users, processes and applications. Integrity means that data is protected from manipulation and there-fore cannot be changed without permission. If one of these areas is missing, data security is no longer guaranteed. 

DCU: 

Dispersion compensation units (DCU) can be used in optical networks to compen-sate the broadening of a light pulse in optical waveguides. This broadening is known as dispersion and leads to a limitation of the transmission bandwidth. Typi-cally a DCU module offers a fixed dispersion value, although compensation units with variable values are also available. Such a unit can easily be inserted into a fi-ber optic link as it has fiber optic connectors for input and output. The insertion loss-es can be significant but can be improved with a fiber amplifier. Such units are often placed between two fiber amplifiers. For effective compensation, the DCU was manufactured in such a way that it works over the entire bandwidth from 1525 to 1565 nanometer. 

Device control is the possibility to prevent data loss. Device Control prevents remov-able media, optical drives and wireless network protocols from being accessed. This security method can prevent malware from spreading further on the target device (e.g. a computer) via a USB stick, for example. In many companies, device control is part of the security strategy, so that, for example, only certain removable media can be connected to a target device. It is even possible to filter the file types. This means that only certain file types can be transferred to the target device. 

The Dynamic Host Configuration Protocol (DHCP) is a client / server protocol from computer technology. Clients are assigned in computer networks by a server. The DHCP protocol makes it much easier to assign a device within a network. In a network based on TCP / IP, each device must have a unique IP address. This is the on-ly way for the device to access the data within the network. If the DHCP protocol were not used, the IP address of each individual device that is moved from one sub-net to another would have to be assigned manually. Devices removed from the network would then also have to be configured manually again. The DHCP protocol automates this entire process. 

DHCP Snooping: 

DHCP snooping is a layer 2 security technology incorporated into the operating system of a network switch. This security layer blocks any network traffic via DHCP (Dynamic Host Configuration Protocol) that is recognized as dangerous or untrusted. DHCP snooping prevents unauthorized DHCP servers from offering IP addresses to DHCP clients. DHCP snooping determines whether incoming DHCP messages originate from trusted or untrusted sources and intercepts them accordingly. This security technology makes use of the DHCP snooping database to check whether the messages are from authorized sources. All hosts that are identified as untrusted are listed in the database. 

A dual inline memory module is a memory that is similar to the main memory (RAM). The DIMM module, a double-row memory chip, consists of one or more RAM chips and a circuit board. These are connected to the motherboard from the computer. The integrated circuits of a dual inline memory module offer processing units such as servers, for example, the possibility of dynamically reading and writing information in the shortest possible time. They have between 72 and 240 pins. DIMM modules are used in servers, in PCs with motherboards and in other processing units. Dual in-line memory modules have notches in different places. So they can be installed eas-ily and the incorrect installation is as good as impossible. 

Disaster recovery means also emergency recovery or data recovery. Disaster recov-ery is part of security planning in IT and implies that files such as photos, videos, etc. and other IT services have been deleted or become unusable, for example due to force majeure (fire, floods, power outages). With data recovery, the risk of failure of servers, data storage devices, telephone systems and networks in organizations and companies is to be kept as low as possible. The Disaster Recovery Plan (DRP) lays down measures and rules on how the company must react in the event of a disrup-tion. 

A Digital Media Player (DMP) is a device that is ideally suited as a complete interactive multimedia device for commercial purposes. The administration of a digital media player is usually done via a clearly arranged web interface. This can be called up via the company network using a permanently assigned IP address. The DMP is able to transmit multimedia content live, play on-demand videos, display graphics and tickers in text form. In addition, updates can be made available to individual persons or to the entire company network. The administrator is also able to control and schedule the frequency and duration of content playback. Another advantage is the low maintenance and implementation effort for IT departments. This results in only low additional network costs. 

Put simply, the Domain Name System (DNS for short) is the "telephone book" for the internet. Every computer or server has a unique IP address, similar to a human fingerprint. To find out someone's telephone number, you search for their name in a telephone book. The DNS also looks for the computer name to find out the unique IP address of the computer or server. The IP address is then used to establish a connection to the server. The Domain Name System resolves computer names into IP addresses and vice versa. To do this, the DNS accesses a central database. The information in this central database is distributed among thousands of name servers (so-called DNS servers). 

DOS: 

A Disk Operating System (DOS) is the operating system of a computer. The main task of the operating system is to read and store data. In the past, IBM delivered its business computers with the DOS operating system. However, this term became famous through Microsoft and Bill Gates, who marketed the Microsoft version of this operating system as MS-DOS. DOS uses a simple command line and does not have its own graphical user interface. This made it very cumbersome for ordinary computer users to use. Today's Windows operating systems still support DOS or the command line, which can be used to execute various computer commands. 

A Disaster Recovery as a Service (DRaaS) is a service provided by cloud providers. If an incident occurs, for example due to cyber attacks, power outages, natural disasters, etc., companies have the option of restoring their data, which has been previously backed up in the cloud, to a DRaaS provider. With an "as-a-service" model, the company does not need to back up its data itself (if it does not have enough resources, for example), but the third-party provider takes over the complete backup and recovery in the event of a disaster. The company therefore does not need to worry about the (often costly) backup and restore of the data. 

The Exterior Gateway Protocol (EGP) controls the communication between routers of different autonomous systems (independent networks). The EGP is used to exchange routing tables with neighbouring routers - also called edge routers. Each autonomous network system has at least one edge router, which is regarded as the last internally managed device by an AS. The mutual exchange of the routing tables takes place via these edge routers in intervals of up to 480 seconds. The routing tables transmit information on the accessible IP addresses, a list of all known routers, as well as path information in order to always select the best possible route for the transfer of network data to each router. 

Endpoint Security protects devices that are integrated into a network from various attacks. In addition to the term endpoint security, the synonyms endpoint security, endpoint security and endpoint protection are used. Various technical and organisational measures ensure that unauthorised persons cannot access the devices and thus cause damage. Devices that can be protected with endpoint security include PCs and notebooks, tablets, smartphones, printers etc. Endpoint security protects against dangers such as viruses and ransomware, among others. For example, firewalls and access controls as well as other security measures are used for protection. 

An Ethernet is a wired data network that connects hardware/software. In most cases, the connection is established via a LAN cable, which is why an Ethernet is also referred to as LAN technology. The Ethernet enables end devices to exchange data with each other. End devices include, for example, printers, servers, computers, etc. These interconnected devices form a local network that sends data packets back and forth between the individual devices via the so-called Ethernet protocol. The protocol that is currently most commonly used is the IEEE 802.3. protocol. In earlier times, up to 3 megabits per second could be transmitted with the Ethernet protocol, whereas nowadays up to 1000 megabits per second are possible. 

The Ethernet connection box, or EAD for short, was used for Ethernet connections. In the early 1980s, EADs supported IT administrators in their work. Before that, data transmission took place via coaxial cable. At that time, the entire network had to be switched off as soon as a new device was to be connected or repaired. The reason for this was the principle of series connection that the networks followed. This meant that quite a few tasks of the IT administrators could only be done after office hours. EADs provided the solution, so that plugging in or unplugging devices became possible without paralysing the entire network. In the 1990s, the use of EADs decreased, so that they are now considered obsolete. 

In an exploit, vulnerabilities in a computer program are systematically exploited. Cyber criminals use exploits to try to find vulnerabilities in programmes and cause damage. Exploits are programmes that find security gaps in installed programmes and use these gaps to attack. These include viruses and ransomware. They are hidden in a Word document, for example, or sneak onto one's own computer unnoticed by visiting a virus-infected website. The malicious code is then stored in the computer's main memory. The exploits now change the programme code in the security hole of the affected programme. The injected malicious code is now executed at the corresponding point in the programme. Exploits can be prevented by, among other things, up-to-date software and security updates. 

FDDI (Fiber Dístributed Data Interface) is an “old” fiber optic technology that reached its peak especially during the Cold War. With data rates up to 100 Mbit/s, it was possible to build complex and widely ramified high-speed networks using the new FDDI standard. They were often used, for example, in research institutions and large companies. Until today the usage of FDDI has strongly decreased. So it is rather used for smaller networks that are to be linked to form a large high-performance network. 

In file sharing, files are exchanged or shared among each other. In most cases, files are exchanged between users on the internet. A file-sharing network is used for this purpose. The files themselves are either located directly on the computers of the various users or on distributed servers that the users use. To use file sharing, a special programme is needed. Corporate file sharing solutions include Dropbox, Dracoon, IBM, GlobalScape and MOVEit. 

A firewall is a network security device that monitors incoming and outgoing network traffic. Based on a set of defined security rules, the firewall decides whether to allow or block specific traffic. Firewalls have been the first line of defense in protecting networks for over 25 years. They act as a barrier between protected and controlled areas of the internal, trusted network and untrusted, external networks. A firewall is either hardware-based, software-based, or a combination of both. There are various firewall systems that can be used depending on the network.

Firmware is the term used to describe programs that are installed by manufacturers on the hardware they sell - in other words, operating software for the respective device. Firmware ensures that the network device is usable at all. It is installed on the flash memory of the hardware and cannot be changed by the end customer. Firmware only can be adjusted only with specific tools, but this will void the warranty, and, in the worst case, the network device will no longer be usable if it is incorrectly modified. Hardware manufacturers often update the firmware on their devices at regular intervals to make the hardware even more powerful, to apply security updates and to provide new functionalities. 

Flash Core Modules, FCM for short, are computer data storage modules with solid-state technology. The modules are based on the well-known NAND memory and have supplementary functions to the already given possibilities of flash. These functions include data reduction, durability and also the Non-Volatile Memory Express (NVMe) interface. For example, due to data compression, raw storage capacities increase to 4.8 TB 9.6 TB, 19.2 TB and 38.4 TB. 

Flash memory is a data storage medium that is built into the hardware. It does not require its own power supply and is not dependent on moving parts. Flash memory evolved from EEPROM (Electrical Erasable and Programmable Read Only Memory) and is installed in most devices. Similar to hard drives, flash memory permanently retains the data that is stored on it. Also, data is read out, written, and erased in data blocks of 64, 128, etc. bytes. 

A File Transfer Protocol (FTP) is a "file transfer protocol" that transfers files over different IP networks from the server to the client and vice versa. There are certain FTP programs which have been developed for this purpose. For example, when a website is to be put online, the files for the website are usually completed locally and transferred via FTP program to the server where the website is hosted. The File Transfer Protocol is located in layer 7 of the OSI layer model and is also used to create directories, rename, create, move, and delete files. 

The term "gateway" comes from computer science or information and communication technology and is a kind of intermediary. It mediates between different protocols used by two systems. Gateways make it possible for two systems to communicate with each other even though they are not necessarily compatible with each other. For example, computers, networks, or programs installed on the computers are considered as a system. Gateways are used to establish communication among IP devices that can only communicate with each other via older radio protocols. Gateways convert the incoming data into the correspondingly required target data. 

Gigabyte (GB) is a unit used in computer science and digital technology. This size unit is used in many storage devices such as hard disks and provides information about how much data fits on the storage medium. Likewise, gigabyte is the size unit that indicates how large a file is. Converted into bytes, a gigabyte is 1,000,000,000 bytes. In computer science, the smallest unit is the bit (binary bit). Therefore, the smallest unit, the bit, is used as the basis for gigabytes. However, computers only know two states: 0 and 1. This is also known as the binary system (also dual system). 

Gigahertz (GHz) is a multiple of the base unit hertz (Hz). The German physicist Rudolf Hertz coined the term. Hertz indicates how many oscillations are emitted per second. In computer technology, gigahertz refers to the clock rate of the processor. If, for example, a processor has a 2 GHz processor, then it manages 2 billion cycles per second. In radio technology (for example WLAN) there is the 2.4 GHz or 5 GHz (or 5.8 GHz) frequency. In most cases, 2.4 GHz networks are more resistant to interference than 5 GHz networks, but the 5 GHz band manages much higher transmission rates and distances. Antennas can be used to extend the radio range of the WLAN network. 

GitHub is a web-based application that software developers use to manage their source code. Both developers and users of the respective software have the possibility to view changes to the source code and thus get an exact overview of what exactly was changed in the source code and when. GitHub is a combination of version control and Git. When software developers create software, it is regularly updated with new features and errors (bugs) are fixed. Version control now offers the possibility that several developers work on one software project. 

The GSM mobile communications network is also known as the 2G network. 2G means it was the second generation after the first-generation analog standard, which in Germany included the A, B and C networks. The original plan for the GSM network was to replace analog mobile networks. GSM was released in 1990 as a new mobile communications standard and served mobile networks that were digital capable. GSM quickly became the new mobile communications standard worldwide. In addition to telephony, the GSM network was also used for short messages and packet data transmission. In the meantime, there was already a successor in the form of 3G (UMTS), which has already been superseded by 4G (LTE) and currently by the fifth generation, the 5G standard, although some of the earlier generations are still in operation. 

The term hacker is derived from the English "to hack" and means something like penetrating into systems. A hacker is a person who breaks into computer/IT systems. In the 1980s, this developed into a scene. Parts of the hacker scene see their mission in pointing out and eliminating security gaps. In the public context, however, since 1983 the term "hacker" has increasingly been associated with negative and criminal activities such as the explicit exploitation of security gaps and the hijacking of data records (e.g. passwords). 

The hard drive, also called hard disk or hard disk drive (HDD), is a storage medium that works on a magnetic basis and on the surface of which data is read and written in a rotating manner. The surface of the hard drive is magnetically coated. When information or data is written to the hard drive, it is magnetized without touching it. Remaining magnetization (remanence) ensures that the information is saved. During the reading process, the hard disk scans the surface of the magnetization and reads out the information. Hard drives nowadays have a storage capacity of up to 10 terabytes (TB). 

Hard disk encryption (also called Full-Disk Encryption FDE) ensures that the data stored on a hard disk is protected from unauthorized access. To make this possible, the data is partially or fully encrypted. When booting, it is necessary that the data on the hard drive is either unencrypted or a special boot manager is available that decrypts the data. A key is required to read out the data. The key is obtained through authentication, for example by entering a user name and password. If the key is activated, the data is automatically encrypted or decrypted. 

Hardware includes all technical components of a computer, tablet, or smartphone. Furthermore, peripheral devices such as external hard drives, routers, beamers, switches, servers, and many other devices also belong to the term hardware. The technical components of a computer include the mainboard, processor, graphics card, RAM, optical drives, and input and output devices. In contrast to software, which is immaterial, hardware is a component that can be touched physically. 

The hard disk drive (HDD) is still one of the most important magnetic storage devices in computer technology (along with the SSD). The HDD uses magnetization technology to store a wide variety of data on rotating disks. The disks in the HDD are directly on top of each other. Like the pickup on a record player, the hard disk drive has a small actuator arm. This is part of the read and write head. However, when reading and writing data on the HDD, the actuator arm moves back and forth and jumps to the required storage location on the HDD, unlike the record pickup. The HDD is slower than a SSD, but it usually has a much longer lifespan than a SSD. 

IDS is the Intrusion Detection System. It is a system that detects attacks by intruders who attack computer systems and computer networks. Either the IDS is used alongside a firewall as an addition or as a standalone system that monitors the networks. The military designed the host-based IDS (HIDS). As a result, the HIDS is among the longest-used detection systems against intruders. When a HIDS is used, it must be installed and configured independently on each computer that is to be monitored. 

VoIP telephony (Voice over IP) is nowadays a common standard for telephony via the Internet. It is therefore crucial for companies to decide whether IP-based telephony should rather be installed locally and thus operated on site, or whether a hosting provider in the form of a cloud service is the better alternative. With hosted IP telephony, the telephone system is merely virtual, which saves expensive and inconvenient hardware purchases. An external service provider (managed service) takes care of everything needed to operate the software-based IP telephony. The external provider takes care of installation and configuration as well as ongoing support. 

A hub is a device that connects to several network devices by means of a cable. A hub usually has between 4 and 16 ports, each of which connects one network device to the hub via a patch cable. The functionality of hubs is limited exclusively to the distribution of information. There is no sorting of the received data packets. This means that the information received by the hub is transferred to all connected devices, even if they are not actually the recipients. Because of this, the load on the bandwidth of the entire network increases. For this reason and because of the high security vulnerabilities of a hub, they are rarely used nowadays. 

A hybrid cloud is a combination of a private cloud and one or several public clouds. With the help of special software, communication can be exchanged between the private and the public cloud(s). Companies are more flexible with the hybrid cloud solution than with a conventional cloud solution. Workloads can be moved back and forth between the two cloud variants, depending on the requirements. In addition, companies control their private data much more effectively with the hybrid solution. Private data is stored in the private cloud and data intended for the public is stored in the public cloud. 

Infrastructure as a Service (IaaS) is an online service that provides computing, storage, and network resources for a fee. Access to the resources corresponds to demand and usage. For companies, the IaaS solution reduces the maintenance effort within the data centers. In addition, the company saves costs and receives business data in real time. The IaaS helps to deploy new applications in a fixed manner. When a company uses Infrastructure as a Service, it eliminates the need to purchase and manage data centers and physically existing servers. The company pays only for what it needs and consumes in terms of resources. 

The Internet Assigned Numbers Authority (IANA), is responsible for names and numbering systems on the internet. These form the basis for addressing websites. Overall, the IANA has 3 major areas of responsibility. These include domain names, the allocation and assignment of IP address blocks and the administration of names and designations for Internet protocols. The IANA was founded in 1988 and is thus one of the oldest institutions on the internet. The non-profit organisation ICANN (Internet Corporation for Assigned Names and Numbers), formed 10 years later, was charged with carrying out the IANA function. Since autumn 2016 the ICANN has had complete control over the functions of IANA. Before that, IANA was always supervised by the US government. 

The Internet Corporation for Assigned Names and Numbers (ICANN) is the highest internet-authority. The purpose of the non-profit organisation is to maintain the operational stability of the internet. When it was founded in 1998, the main focus was on the administration of IANA and its functions. Today, IANA is only one of ICANN’s areas of responsibility. The US Department of Commerce was in charge of controlling ICANN until 2009. Today, the ICANN is under international supervision. 

An Identity Services Engine (ISE) is a Cisco-provided solution that focuses on protecting the entire workplace. ISE enables flexible mobility with controllable access to devices and users and ensures full transparency of the users and devices involved. For IT departments, the Identity Services Engine provides successful protection against all attacks across the entire network. For guests, both mobile and desktop, the ISE provides the ability to be connected to the network in the shortest possible time. Network policies are created and managed from a central location. This means maximum security convenience for the end user. 

An intrusion detection system (IDS) is a system that detects attacks targeting servers, networks, and computers at an early stage. The Intrusion Detection System is often an addition to the firewall. If an attack is detected by the IDS, the system informs the responsible employee(s) about the attack. An attack follows a certain pattern, which the system recognizes. In many cases, the IDS runs as self-running hardware or as software installed on a computer system. The IDS differs from the Intrusion Prevention System (IPS) in that it only has an informative character in the event of an attack, while the IPS also knows how to prevent attacks. 

The Institute of Electrical and Electronics Engineers (IEEE for short) is a professional association whose task is the standardisation of computer programs and techniques. The IEEE 802 project, in which network standards are defined, was started in 1980. With the help of the standardisation of network protocols, it is ensured that a connection of different types of devices with different types of networks is possible and that their problem-free cooperation is guaranteed. Through the IEEE 802 standards, Internet services and technologies are required to follow the recommended procedures. Without these standards, manufacturers could introduce network hardware designed only for specific computers. Therefore, difficulties could arise in connecting to other systems that use other networking components. 

IEEE 802.1aq is a protocol standard that positively influences teh data flow. Shortest Path Bridging, or SPB for short, makes better use of existing resources. With SPB, it is always important to use the shortest path to connect network nodes with each other. For this purpose, existing network connections should be actively used and not kept freee for possivble complications. By aiming to use the shortest path for establishing the connection, SPB ensures a fast connection, especially within data centres. 

IEEE 802.3ae: 

The IEEE 802.3ae is an Ethernet standard written by the Institute of Electrical and Electronics Engineers. In this standard, the technical standards for Ethernet connection with a transmission rate of up to 10 Gigabytes per second. In the beginning the standard only covered data transmission via fibre optic cables. It is being adapted because 10 gigabyte connections based on copper are also used today. These are usually cheaper than fibre optic cables and are therefore often used to connect local network components such as switches. 

The Internal Gateway Protocol (IGP for short) is used to promote the exchange of routing information between routers within an autonomous system. The IGP can be used on the one hand to disseminate information about the availability of routers and on the other hand to check the possible paths for data packets. This exchange of information is permanent within an autonomous system. The information obtained then uses the Internet Protocol (IP) or other network protocols to determine the best possible path for data packets. 

IOPS is the abbreviation for Input/Output Operations per Second. The IOPS shows a number of executable input and output commands per second by the SSD (Solid State Drive). The SSD is a type of non-volatile storage medium. The IOPS value shows the speed of communication between the processor of a computer and the input or output units. That means: the higher the IOPS value, the faster the data medium. In the course of time, the value decreases due to a full cache in many SSDs. 

The Internet Protocol (IP) is a network standard that is used worldwide. Two or more devices communicate with each other thanks to the Internet Protocol. Data can be exchanged without any problems among each other. Devices that communicate with each other via the Internet Protocol have a unique IP address. This makes each device uniquely identifiable. These unique IP addresses ensure that the data packets also arrive at the recipient for whom they are intended. The Internet protocol is used in private networks, corporate networks, and intranets. 

The Intrusion Prevention System (IPS) detects at an early stage whether networks and entire systems on computers are under attack and fends off these attacks automatically. The IPS can also be seen as additional protection to the firewall. However, the Intrusion Prevention System must be distinguished from the Intrusion Detection System (IDS). The IDS takes on a passive role where it detects and identifies attacks, but only informs users and admins about the attack. Whereas the IPS also detects attacks, but actively intervenes on its own to defend against the attacks. It can block certain data bundles in the event of an attack. The intrusion prevention system also directly prevents certain connections in the event of an attack. 

Internet Protocol Security (IPsec) is a set of extensions to the traditional Internet Protocol (IP). IPsec ensures that communication in IP networks is secure. The extensions provided by IPsec encrypt and authenticate the data that is transmitted over the Internet Protocol. Since the IP network is insecure on its own, IPsec provides protection within the IP network as an additional step. With transport mode and a tunnel mode, Internet Protocol Security has two effective mechanisms. Transport mode establishes a point-to-point connection directly, while tunnel mode establishes a secure tunnel connection via two gateways. 

The term IT (information technology) has established itself in the German language and refers to a broad range of terms that include hardware, software, and services. Hardware includes, for example, mobile devices, printers, PCs, monitors, etc. Software includes applications (application programs) and operating systems. IT services are consulting services, maintenance of hardware and software, installation of software, programming and testing of software. IT includes business analytics, system administration, IT security, network, application development, digitization, and helpdesk. 

In IT remarketing, used IT hardware is purchased, refurbished (equipment is cleaned and technically reconditioned) and then resold as refurbished hardware. This entire process is also referred to as "refurbishment". The resale of used hardware is sustainable and environmentally friendly, as the old hardware is recycled and refurbished. When buying used hardware, it is important to ensure that the data on the used equipment is deleted completely and securely. Otherwise, there is a risk that sensitive data can be recovered by the new buyers. 

IT security is also referred to as cyber security or Internet security and implies protecting IT systems from threats and attacks. Files, computers, or entire networks can be attacked in that process. IT security includes both organizational and technical measures that are intended to protect IT systems from threats. The term cyber security includes protective measures such as firewalls, proxy servers, virus scanners, rights management, and access controls. IT security also differs from information security. While information security deals with the protection of information, IT security protects technical devices or IT systems. 

Jitter describes the fluctuation of the clock signal (clock jitter) during the transmission of digital signals. Clock jitter can occur if there is electromagnetic interference, or the clock is incorrectly synchronized. In the network area, jitter is used to describe the variations in the runtime of data packets. If the runtime fluctuates, this is extremely problematic for data transmission. Runtime fluctuations have a particularly critical effect on applications in real time, such as Voice over IP (VoIP) telephony. Such applications then have high jitter values when runtime fluctuations occur. A jitter buffer helps to minimize the runtime fluctuations and thus the delays in transmissions. 

LAN is the abbreviation for Local Area Network and means "local network". As a network, the LAN extends only over a limited space, for example a single building. Several devices such as printers, PCs and servers are connected to a LAN. Via the local network, all devices connected to the network can connect to each other and use services provided via the LAN. LAN networks are usually connected by twisted pair cables. The LAN differs from the WAN (Wide Area Network) in that the Wide Area Network connects devices over a larger spatial distance. 

A layer is given the greatest importance in the context of the OSI model in IT. In terms of the OSI model, layers mean the differentiation of the various protocol levels. For example: The transfer of data by using a network cable is carried out by electrical impulses. The data transmission of web servers takes place via protocols such as http or https.These are on a significantly higher level. The OSI model consists of 7 layers which are using hierarchical communication with each other. 

Link-local Multicast Name Resolution: 

The Link-local Multicast Name Resolution (LLMNR) is a protocol for name resolution of IPv4 and IPv6 addresses in local networks. The protocol is also used to identify neighbouring computers. This protocol is primarily found in Microsoft operating systems. LLMNR is a kind of extension for the NetBOIS protocol. The NetBOIS protocol is exclusively designed by IPv4 addresses. NetBOIS was also developed especially for the manufacturer Microsoft. The addition of LLMNR was also necessary because NetBOIS distributed system information unencrypted over the network. LLMNR increases data security accordingly. Both protocols therefore work parallel in the system. 

Locally Administered Address, LAA for short, refers to a MAC address of a network card. This MAC address was assigned locally by software and overwrites the Universally Administered Address originally specified by the manufacturer. By means of LAA, the predefined MAC address of a network component can be individually changed. Nevertheless, the possibility of freely assignable MAC addresses is often used to disguise identities and gain unauthorised network access. 

The Long Range Wide Area Network (LoRaWAN) enables data to be sent over long distances - even from remote or hard-to-reach locations. The special feature of LoRaWAN lies in the energy-efficient, secure and cost-effective transmission of information and data. Here, the use of narrowband technology together with battery-powered and wireless sensors is sufficient. The transfer of data is carried out by 3 essential components of the LoRaWAN. These include the sensor, which is responsible for detecting and encoding data. Then, the sensor sends this data to all gateways in its vicinity. The second component are the Gateways, which receive the data. After receiving the Gateways are responsible for the transfer to the server. In the LoRa server, the last component, the incoming data is processed, visualised and stored if necessary. 

Malware is malicious software that is unintentionally downloaded and installed by the user. This distinguishes malware from computer viruses that spread over the network or other computers. There are different types of malware such as adware, spyware, trojans or ransomware. These differ in the way the user learns about an infection. While the user is informed directly about the presence of ransomware and this malware can allegedly only be removed by making a payment, other types work in the background and are often not noticed by the user. Malware is often distributed via e-mails, where a user clicks on a link to install it on the device. Anti-virus systems often recognize the malware and block the download. 

A Metropolitan Area Network (MAN) is a network that connects several LANs with each other. The Metropolitan Area Network is also known as the campus network or city network. In many cases, cities connect to each other with a MAN. The MAN is mainly used for transmitting data and video, for which high speed is required. MAN backbone lines use fiber optics for the high transmission rates. Metro Ethernet is used to transmit the data. Metro Ethernet enables high speeds that are significantly higher than the speed of the Internet. This makes them comparable with LAN networks in terms of speed. 

Managed: 

For building a private or corporate network via network switches, there is a choice between managed and unmanaged switches. Managed Switches are very price-intensive. Because of many extended features they are primarily used in the business sector or large networks. Managed Switches also have high security standards through access control lists, communication encryption or remote access. Due to the adaptability to the network and the additional features that a managed switch offers, before the initial operation a complex configuration is necessary. 

Managed Service Providers (MSP) are external service providers who offer a wide range of (IT) services. Among other things, they are responsible for keeping their client's software up to date, monitoring the systems, identifying and eliminating faults in advance, and keeping the client's entire system landscape functional. Most of the services offered by a managed service provider are regular services. 

The Medium Dependent Interface, MDI for short, is superficially a socket for network cables. More precisely, Medium Dependent Interfaces are connections of network cards for network cables. More precisely, Medium Dependent Interfaces are connections of network cards for network cables. Medium-dependent interfaces can be used to connect any network devices directly and indirectly to each other. The reason for this is the special arrangement of the individual wires in the network cable. In order not to block the data exchange, the signal output of a device is linked with the signal input of another component. 

The Metro Ethernet has network connections that use the Ethernet standard. In contrast to conventional LAN connections, Metro Ethernet can cover longer distances. The Metro Ethernet uses the so-called Carrier Ethernet technology so that high-quality connections can be established. Carrier Ethernet can connect different company locations with each other. It is also used to establish transmissions via the Metropolitan Area Network (MAN) or the Wide Area Network (WAN). 

Several devices such as computers or notebooks are connected to each other in a network via a network module or network card. In most cases, current devices support Ethernet connection. The network module is responsible for enabling several devices to communicate with each other within a network. The network card is also capable of reloading the operating system within the network or rebooting the computers in the network. Network modules are available in various designs. These include integrated network modules that are installed directly in the computer, in routers or in other end devices, PCI and PCIe network modules, PCMCIA network adapters, USB network modules or even a Fibre Channel (FC) card. 

Multiprotocol Label Switching (MPLS) is a network technology that determines the path of data to be transmitted within a network. MPLS as a network protocol specifies a specific path for data transmission in connectionless MPLS networks, i.e. between two locations. In contrast to classic IP networks, the devices in the MPLS network, e.g. routers, do not have to make individual forwarding decisions, but the forwarding is determined by the device using a label before the start of the data transfer. Thus, the multiprotocol label switching can forward data faster than other systems. 

NAS is the abbreviation for Network Attached Storages and is a system that is used to increase the storage capacity in networks. NAS servers are becoming more and more popular in companies of various industries as they offer an effective and cost-effective solution for data storage. Among other things the function of a NAS server is very versatile, so the server provides the user PC with a local network. Users or other network users can access this network in order to archive or save files. With NAS systems, data is accessible at all times. The NAS storage can be flexibly adapted to the respective requirements of the users, e.g. by adding additional storage capacity. 

Netflow is a protocol developed by Cisco, which is now used as a standard protocol to log and to evaluate the data as so-called IP flows between routers and Layer 3 switches. The information for the flows is evaluated directly by the devices by transmitting the information to various collectors within the network. Subsequently, the collected data can be analysed and processed using specific software. The purpose of the protocol is to monitor and analyse data traffic in the network. The Netflow protocol provides much more detailed insights into the IP data streams than the Simple Network Management Protocol (SNMP). 

A network cable physically connects participants that are located in a network. Network cables are available in different types and can be distinguished by their structure and the material used. The copper cable is available either as a coaxial cable or as a twisted pair cable. The fiber optic cables, on the other hand, contain glass or plastic as base materials. Network cables differ within various categories (CAT). There are categories 1 to 7 (CAT 1 to CAT 7) and they indicate how powerful a network cable is. The transmission rate of the network cable indicates how fast the network cable transmits data. The higher a network cable is in a category, the better the cable is, as it brings additional performance to cables in lower categories. 

A network card is also called a network adapter or NIC (Network Interface Controller). A network card can be an Ethernet adapter or a WLAN adapter. The network card is necessary to connect a computer to a network. A network already exists when two computer are connected or communicating with each other. There are different types of networks, such as Arcnet, Ethernet and Token Ring. For each of these types of networks, the corresponding network card is required. The most common are the WLAN as well as the Ethernet network card. 

For network licenses, license protection is provided by a special network key, which can be attached to or installed on any computer accessible in the network. Unlike a software license, a network license is usually located on a license server and is therefore not permanently bound to a computer. Hence, it is not a single license for a local computer. The license server dynamically assigns licenses to the individual computers of the network for a certain period. Once this period has expired, the license is withdrawn from the affected computer in the network. 

The Network-based Intrusion Detection System is responsible for monitoring data traffic in a network. To prevent a NIDS from being overused, it is useful to divide it into smaller segments. Once the system is registered on the network, the traffic passing through the responsible segment is guarded and recorded. When the NIDS has examined the data, the signature of the data can be used to verify if the data is sound or if it is an attack. The NIDS accesses a specific list in which damaged data traffic is described and what should happen to this data. NIDS must be placed in the network in a well-dosed manner, otherwise the network will be overloaded, and network performance will drop significantly. 

Open source was originally traced back to so-called open-source software in which the source code is made publicly available. This allows third parties, for example other developers, to view the source code, modify it and improve or adapt the corresponding open-source software. As a rule, software with an open-source license is free of charge. In the case of open-source software, the software is usually developed by several developers within a community and checked for errors by peer reviews. Open-source software is usually cheaper, much more flexible and has a higher life cycle than commercial software from companies or individuals. Most open-source software projects use GitHub as a publishing platform. With GitHub one makes use of so-called repositories. One of the most popular open-source software projects is Linux. 

Optical fibers consist of quartz glass or quartz sand, which is used for transmission. For example, a fiber optic cable, which is made up of various glass fibers, is a cable used to transmit signals. Thanks to fiber optic cables, light signals are transmitted at the speed of light over a long distance. In doing so, fiber optic cables can transmit a huge amount of data. Several optical fibers make up a bundle and form the fiber optic cable. A single optical fiber is almost as thin as a single human hair. It consists of a core, coating and outer sheath. 

The Open Systems Interconnection Model (OSI Model) is often called the 7-Layer Model because of 7 individual layers. The model is used to describe and define the communication between systems. The use of the OSI model is intended to facilitate communication and to create compatibilities. Within the model, 7 layers have clearly defined tasks. The first 4 layers are transport oriented and the other layers from 5 to 7 are application oriented. The communication between the layers takes place hierarchically with the layer directly below or above it. 

Platform as a Service (PaaS) provides a platform within a cloud in which applications can be programmed or developed. There is a close connection to similar services such as Software as a Service (SaaS) or Infrastructure as a Service (IaaS). Platform as a Service is based on Infrastructure as a Service but provides additional features such as the provision of hardware. A development environment is also usually integrated and can be used by PaaS users. Adaptations to hardware and software are not necessary because the service runs via a cloud and therefore no additional hardware and software must be purchased. 

Patches are security holes or other errors in the source code of a software. As a rule, software is never error-free and is always improved by patches. Patch management strategically controls the application of patches to the software in question and is now a standard part of the services offered by most IT service providers. The main tasks of patch management are to monitor patches and to deliver or install provided patches to the target devices within a short time. Patch management therefore includes planning, procuring and checking patches. 

PCI (Peripheral Component Interconnect) is considered a standard in a communication bus over which an extensive exchange of data takes place. The bus connects various peripheral hardware such as plug-in cards with the chip of the computer. The predecessor of Peripheral Component Interconnect was the ISA bus or Vesa local bus until the 1990s. The PCI bus allows connected plug-in cards to be automatically recognized and configured by the system. Plug-in cards include network cards, graphics cards or modem cards. Since the transfer speed became higher and higher over the years, PCI Express appeared in 2005, which replaced the normal PCI and enables higher transfer speeds. 

Using PoE (Power over Ethernet), network cables can supply devices with data and power via an existing data connection. PoE is particularly advantageous where the installation of power lines is too cumbersome or expensive, since only one PoE cable is required to connect PoE-enabled devices. Devices that are PoE-capable are so-called PSE devices (Power Sourcing Equipment) or PD devices (Powered Device). PSE devices such as network switches or PoE adapters for use with non-PoE switches transmit power. PD devices such as VoIP phones, WLAN access points and static IP surveillance cameras, on the other hand, only use electricity. Certain standards must also be observed for the Power-over-Ethernet transmission of data or power. 

Portfast is a feature for the configuration of switch ports. When the switch port is activated or also in the event of connection failures, the Spanning Tree Protocol (STP) usually starts. The STP includes phases to put the port into the STP forwarding state. The phases of the STP are: Blocking, Listening, Learning and Forwarding. It takes up to 30 seconds for the port to transport user data. With the help of the extension of the STP by Portfast, the change from blocking takes place directly to the last phase, forwarding. The listening and learning stages are bypassed, so the port changes more quickly to the forwarding status. 

A port is part of the IP address. Ports are used to communicate between 2 or more computers with the Internet. For this purpose, data packets are sent to an IP address and specifically assigned to an application or service through certain ports. The ports, numbered consecutively from 0 to 65535, are also divided into 3 groups. The standard ports from 0 to 1023 are the most important ports and are all linked to specific services, such as websites. These port numbers of this group are assigned by the IANA. The port numbers 1024 to 49151 belong to the user port group and are also assigned to certain services (e.g. for the management of networks). The dynamic ports form the last port numbers up to 65535. The allocation of the port numbers depends on the operating system. To protect the computer from viruses, unused ports are automatically closed by a firewall on the computer. 

PPPoA is a network protocol in which PPP stands for "Point to Point Protocol", the alignment of data transmission between any two computers. "oA" means that the computer connection on one side is established at least via classic telephone network (ASDL). The data are exchanged in small packages ("fragmented"). On the contrary, the modern protocol "PPPoE" (PPP over Ethernet) sends data and information in standardised blocks of 1,500 Bytes each. PPPoE is carried out via fast ISDN lines. 

PPPoE (Point-to-Point Protocol over Ethernet) is a protocol that is used to establish a point-to-point connection via the Ethernet. PPPoE uses both the standard PPP (Point-to-Point Protocol) and the Ethernet. It is mostly used by providers to ensure dial-up to the Internet via DSL. Ethernet allows several devices to connect simultaneously via PPPoE. When a router is used, it is responsible for ensuring that a connection to the Internet is successfully established. 

A proxy serves as a server and has the role of an intermediary in a network. It receives requests in the network and forwards them accordingly. When a proxy server receives requests, it uses its own identity for the transfer. So, the proxy serves to secure connections or communication and to disguise them. The proxy thus carries out the network communication itself, so that the identities of client and server remain hidden from the other communication partner. For the functionality of a proxy server, software is required, which is installed either on the client's own computer or on the server. Most often HTTP proxies are used. 

Quality of Service describes the quality of a communications service from the user's perspective. The quality of a service is measured in terms of the extent to which it meets the requirements that users have for this service. Quality of service plays a particularly important role in VoIP telephony. The requirements for quality of service include fast and reliable connections, stable connections, high transmission quality, and trouble-free transmission. 

The Q-Bus is also known as the LSI-11 bus and is one of several bus technologies formerly used on PDP and MicroVAX computer systems. The Q-Bus is less expensive than the Unibus. It uses multiplexing and can thus share address and data signals running on the same line. Initially, the Q-Bus had an address range of 16 bits, which has since been extended to 22 bits. In addition, it now has so-called block transmission modes. Like the Unibus, the Q-Bus uses memory-mapped IO, byte addressing, asynchronous signal exchange, and a strictly separated master-slave relationship between the individual devices connected to the bus. 

QIC (Quarter Inch Cartridge) is a magnetic tape system formerly used to create backups of data. In the 1980s, QIC drives were mainly used in UNIX servers as well as PCs. The data carriers were cassettes (mini-QIC or mini-DC) whose magnetic tapes were up to 460 mm long and up to 6.5 mm wide. Storage capacity was limited to 20 GB. Later, Tandberg Data developed the so-called Multichannel Linear Recording (MLR), which increased the storage capacity up to 50 GB. There were over 40 different types of cartridges with a storage capacity between 15 MB and 50 GB. 

The RAID principle (redundant arrangement of independent hard disks) combines several hard disks into one drive (the so-called logical drive). This logical drive ensures that better data security is guaranteed, which results from redundancy. Hard disks are combined in a hard disk network so that in the event of a power failure or the failure of one of the hard disks, the others remain fully functional. Thus, in the event of a data loss on one hard disk, the same data can still be accessed, given that all hard disks contain the data of the backup. All hard disks in the RAID hard disk array should preferably have the same storage size as well as the same performance characteristics to avoid complications during RAID operation. 

A RAM memory ("Read Access Memory") is a random-access memory. This type of memory is mostly known as main storage. The RAM memory modules are mainly used in computers. It is a volatile memory that serves as the computer's short-term memory. So, when the computer is turned off, the data existing in RAM is erased and is no longer available by the next time the computer is started. RAM is therefore used by the computer for data that is required by the computer on a short-term basis or quickly. The hard disks are supported by the RAM because otherwise they would have to process the data that the RAM processes additionally. 

Ransomware is therefore a so-called "blackmail software" that locks the end device in question and asks the user to pay a ransom so that access to the computer is granted again. Ransomware encrypts the data on the device. Without the corresponding key, the data can no longer be decrypted. The first known attempt to spread ransomware via the Internet was recorded in 2005. Before, it was common for ransomware to be spread through other storage media. Ransomware is part of the malware family and is therefore related to viruses, spyware, Trojans or cryptolockers. 

Redundancy means that data, information, or things that are comparable with each other are available several times (at least twice). The term redundancy comes from the Latin "redundare" and means that things are available in abundance. In IT technology, redundancy is advantageous because it ensures that data, networks, and systems can be accessed even if a malfunction occurs. Components are therefore used more than once with the same installation to be prepared for incidents such as power failures. However, redundancy has a negative impact on databases. If data appears more than once (redundantly) in databases, this leads to incorrect database queries and slows down the database. It is therefore important to avoid redundant data in databases. 

In refurbishment, used components are overhauled or repaired and then resold or reused. In the network sector, refurbishment means that routers, switches, servers, modules, transceivers, and other components are overhauled and then reused or resold. Refurbishment helps to protect the environment because used equipment can be reused instead of being disposed of. This avoids unnecessary waste and conserves resources that would otherwise be needed to build new components. The characteristic features of refurbished equipment are its perfect technical condition, only slight signs of use, and the price which is up to 50 percent cheaper than new when purchased. 

Repeaters are devices or components that extend WLAN transmission paths. So, it is possible for the range of a network to be much longer than it would be in its original state, without the repeater. Repeaters receive signals from the router and pass them on. A repeater is called a HUB if it has more than one port (input and output). Repeaters can be used for WLAN, Ethernet, mobile network, and many other types of transmission and can be connected either by cable or wirelessly. Likewise, several repeaters can be connected in series. For example, certain repeaters can be used to create a so-called WLAN mesh. With WLAN mesh, several repeaters create a single WLAN network from several WLAN networks. 

Exploit in the context of IT means that vulnerabilities in the source code of a program are exploited to cause damage. The attacker exploits program errors and security holes in the source code of programs to gain access to the data of the computer or entire computer systems. Especially on systems equipped with the Android operating system, so-called root exploits are often used by hackers. A root exploit belongs to the malware category and is one of the most dangerous types of malware. By means of the root exploit, the hacker obtains the so-called root access rights via the operating system kernel to override the complete security systems and have full access to the system. 

A key cornerstone for the progress of digitization is a reliably functioning network. Elementary building blocks of such a network include routers. Network routers forward the data packets using a routing table via selected interfaces and thus make data exchange, the so-called routing, possible in the first place. They are like the brains of the network, making sure everything goes in the right place. The most important functions of a router are the modem and WLAN, with the integrated modem ensuring the connection to the Internet. So-called WLAN routers also enable laptops, smartphones and tablets to access the Internet in addition to desktop PCs. 

The Routing Protocol for Low Power and Lossy Networks (RPL) is an IPv6 routing protocol. The protocol is specially designed for wireless networks whose general weak point is the loss of data packets. By means of the protocol, network routes are determined quickly and routing knowledge is exchanged rapidly. The task of the RPL is to ensure the continuous functioning of the communication. The routing protocol maintains this even if individual components are no longer functional due to extreme environmental conditions (heat, cold). 

The abbreviation SaaS stands for Software as a Service and is part of cloud computing. A SaaS model provides that the software used by the user and the associated infrastructure is provided by an external IT service provider and is not the responsibility of the user himself. In this case, the user uses the software as a service and pays a usage and maintenance fee. On the one hand the advantage of a SaaS model is that there are no cost-intensive purchases of server structures for the user and, on the other hand, the provider is responsible for the complete administration, maintenance and updating. The user can thus concentrate solely on using the software. 

In a storage area network (SAN), different storage components, such as hard disks and tape systems, can be interconnected. The storage space then available can be distributed variably over a single or multiple servers. This approach makes the storage area network an extremely flexible and powerful network with high performance. Data in a SAN is accessed on a block basis. The structure of a SAN network is similar to that of a normal LAN network. A SAN runs parallel to a LAN and is responsible for the data transfer of the storage media. 

SATA is also known as Serial ATA, or S-ATA, and stands for "Serial Advanced Technology Attachment". SATA is responsible for transferring data from hard drives and removable storage media. SATA's predecessor was ATA (AT Attachement) and, unlike SATA, did not offer parallel data transfer, only serial. In 2000, SATA replaced its predecessor ATA as the standard. Intel was largely involved in the development of the SATA standard. SATA is available in different data rates. With version 3 of SATA, transfer speeds of up to 6 gigabits per second can be achieved. With eSata (external SATA), external storage media can also be connected. 

The Storage Class Memory (SCM) is a new type of memory. The SCM is a storage layer in computing systems. It functions as an intermediate layer between a memory (a volatile working memory) and a storage (a non-volatile hard disk memory). The storage layer serves to increase the efficiency and speed of the systems. At the same time, the SCM is intended to reduce the costs of storage. An important feature of the SCM is that the data is stored after the system is switched off. In contrast to conventional hard disks or SSDs, faster access times and higher data transfer rates are possible with the SCM. However, SCMs are more suitable as an additional storage for SSDs to increase the performance of applications. Therefore, SCM drives are not a replacement for SSDs. 

An SD-WAN is a software-based wide-area network (software-defined wide area network) and thus a virtual WAN network. Companies are extremely flexible with the SD-WAN because they can securely connect users with different applications via LTE and other broadband services. The SD-WAN controls the data traffic within the WAN centrally and securely. The key benefits of an SD-WAN are that it reduces costs through independent data transmission, provides high flexibility between users and applications, is user-friendly with respect to various cloud applications, and greatly simplifies cloud-based management. SD-WANs fully support applications from local data centers, cloud services or SaaS services such as Dropbox or Office 365, and also ensure high performance of the applications.

The term server has its origin from the English word "to serve”. The server is therefore a servant that provides services and resources. It makes the services and resources available to the so-called clients which can be programs, such as the browser, or devices. A server can perform various tasks. For example, it serves as a mail server in relation to e-mail services. There are two types of servers: hardware-based servers as well as software-based servers. A hardware-based server is a computer that is connected to a physical network. It runs a virtual server as the operating system. In a software-based server, this program communicates with the client program. Software-based servers therefore also run on hardware-based servers. 

SFP is short for Small Form-factor Pluggable. This is a connection port to which certain components can be connected to establish a network connection. These components or modules are SFP transceivers that are connected to Gigabit Ethernet connections or Fiber Channel. SFP ports are mainly found in routers and switches. The SFP port has (relatively) small dimensions, which allow it to be installed in network devices with many ports. SFP ports are flexible and future-proof and can be quickly replaced when needed. Network devices with SFP ports can also use other types of transmissions. 

Security vulnerabilities are weak spots that occur in IT hardware, such as network devices and servers. These are errors in the source code of a program that were caused by the programmer(s) of the program. Security vulnerabilities can also occur when additional features are improperly added or when the software is not regularly updated to the latest version. These flaws allow hackers to inject a defective code where the source code was programmed incorrectly. This can create security vulnerabilities in any type of software, from the operating system to various software and firmware. With the vulnerability, hackers can capture (confidential) data, control the device, spy on the user, or destroy the entire system. 

Scalability is the ability of a system to grow. If additional resources are made available to the system, the performance of the system also grows. A distinction must be made between horizontal and vertical scalability. Scalability of a software means that it grows with a powerful system. Accordingly, if the hardware improves, the scalable software should also improve. Scalable software adapts automatically without the source code changing. Vertical scalability accordingly means that the system uses the currently best hardware. Horizontal scalability means that several computers are connected to each other and there are no limits to hardware expandability. Here the limits lie with the software. 

With smart lighting, light sources are networked with each other by means of a wireless network system. More precisely, smart lighting brings together smart light sources into a group via WLAN. Smart Lighting reacts to changes in the environment or user wishes and thus supports more effective and energy-efficient illumination of rooms. The intelligent lighting also has functions such as dimming, colour change or Human Centric Lighting. Control is via app, smartphone, tablet or even a voice command. 

SMTP is the Simple Mail Transfer Protocol. The SMTP protocol is a transmission protocol in the IP network that transmits e-mails. The IMAP and POP3 protocols retrieve and manage mails. The SMTP protocol, on the other hand, can only be used to send mails. In the beginning, the SMTP protocol only understood ASCII characters. However, since the MIME (Multipurpose Internet Mail Extensions) standard was introduced, the protocol can process and use binary files. The Simple Mail Transfer Protocol is a client-server protocol. The client is responsible for establishing a connection to the server and sending the commands. The server then executes the commands and informs the client of the result. 

The Simple Network Management Protocol (SNMP) is used to monitor, control and manage network elements. The network devices can be router, switches, computer or printer with a network management system (NMS). The SNMP is used to get an easier way for the communication of network devices to exchange information.This is done through agents and managers which are using push-and pull-communication. The manager, like software on a computer, requests information from the agent at regular intervals. The Agent is usually a software on the monitored hardware and sends back a response. The Agent is getting the information from the MIB management information base, which is the database. The Agent also reports error messages to the manager. After that, the manager reports the error messages forward to the administrator. 

A software license is a legal agreement made between the software manufacturer and its end users. The software license regulates the terms of use of the respective software. If the end users do not have a valid license, they may not use the software. Regardless of whether the software used is intended for private or commercial use, it must be legally licensed to be installed and used. There are different types of software licenses, such as freeware, open source, and commercial licenses. The well-known commercial licenses include various products from the Microsoft family such as Windows and Office or the graphics programs from Adobe. 

Spam is about unwanted e-mails or junk mail. Nowadays, spam mails literally flood the e-mail inboxes of users. A spam filter provides a remedy against unwanted spam mails. Most e-mail providers have a practical function for reporting spam e-mails. It teaches the e-mail client to recognize these spam mails and to not let them through in the first place. In public forums, chat rooms, etc., everywhere where contact information can be publicly stored, the main e-mail address should never be used, but only a substitute e-mail address. In addition, never respond to spam e-mails and do not download any attachments in spam e-mails. 

The Solid-State Drive (SSD) is not a hard drive in the classical meaning, but a storage medium that uses semiconductor memory to store data. SSD storage media can be used both externally and internally on or in a computer. SSD storage media are very robust, have little wear and have a high speed when reading and writing data. Unlike normal hard disks, SSDs have no moving parts. SSDs are read out via the SATA interface, for example. There are also SSDs that have a PCIe interface and can then be used as a plug-in card. 

With the Secure Shell (SSH) it is possible to establish a secure connection to a web server or another computer on the command line - the so-called shell. Under Windows, the shell is known as the DOS command prompt. On Linux and Mac systems, the shell is also known as the terminal or console. However, a shell can also have a graphical user interface. Before the Secure Shell existed, insecure connections were made using Telnet, Remote Shell, or rlogin, for example. SSH is used to manage servers, transfer files securely, create secure backups, and remotely manage computers. The FTP protocol has also evolved into the "SSH File Transfer Protocol" (SFTP) thanks to SSH. 

A storage router is used in smaller companies to send data to each other via a network. The router itself can be used as a storage medium or can be expanded via an external storage medium with storage capacity that can be changed if necessary. The storage router and the storage medium are usually connected via USB. Storage routers usually have a fast Ethernet connection of up to 1,000 gigabits for fast access and transfer rates. In companies, storage routers are often used in all offices to back up data easily, quickly and effectively. However, in the event of a hardware failure, the data stored on the storage router can be lost. 

The term switch originates from network technology and is a network device that distributes data streams in networks. For this to happen, at least two computers must be connected to the switch. The switch has an intelligent transfer of data to the connected computers, as it can identify and assign them. In this way, the data can be exchanged among each other in a targeted manner. In smaller companies, only a few switches are usually used. In larger companies, on the other hand, many switches with up to 50 ports are used. These are used in so-called racks, as this ensures that the network cables are neatly accommodated. 

TCP/IP stands for Transmission Control Protocol / Internet Protocol and summarizes a number of network protocols. The entire Internet uses the TCP/IP protocol. Data packets of different sizes are sent via the TCP/IP protocol in the LAN and in the WAN. Since the TPC/IP protocol is not dependent on any specific hardware or software, the protocol can be used on all operating systems. TCP/IP can be found in the so-called OSI layer model in layers 3 and 4. These layers are responsible for switching and transporting data. 

Telecommunications is also referred to as signal communications. It refers to any type of communication that takes place over a (greater) distance. This includes any communication that does not take place in the same room. The Telecommunications Act in Germany defines telecommunications in §3 No. 22 as a technical process for sending, transmitting, and receiving signals via telecommunications equipment. Both the sender and the receiver require technical equipment for technical communication. Information is transmitted in text, video, voice, image, and other types of data. Present and past means of communication include, for example, letter post, carrier pigeons, couriers, telephony, and the Internet. 

Transceiver modules are used in Gigabit Ethernet. These are small modules that are responsible for sending and receiving signals in network adapters. Transceiver modules are used in switches and routers. Different cables are used for different distances. In addition, the transmission medium determines whether light, electrical pulses or electromagnetic waves are used. Transceiver modules are small in order to have as many ports as possible available in a small space. They are not only responsible for transmitting and receiving, but also for collision detection autonegation, so that a high data rate is achieved. 

UDP stands for User Datagram Protocol and is a communication protocol from the TCP/IP area. In the OSI layer model, the UDP protocol can be found in the fourth layer, the transport layer. The UDP protocol is connectionless and not secure. Therefore, it is mainly used for applications that have a high fault tolerance and receive and send data on a low latency. The protocol is mainly responsible for transporting data. The DNS (Domain Name Service) system as well as VPNs and other protocols make use of the UDP protocol, which uses ports to distinguish between different applications and requests from users. For the protocol to verify that data has been received correctly, it makes use of various checksums. 

Unicast refers to direct communication between a single sender and a single direct receiver. With unicast, the flow of information takes place exclusively between two network participants. In contrast, the multicast or anycast protocols are used to address many receivers simultaneously. However, the majority of data traffic on the internet is carried out via the unicast principle. For example, every time a user calls up a website, a direct connection is created between the client and the server. 

For building a private or corporate network via network switches, there is a choice between managed and unmanaged switches. Unmanaged switches are usually easy to set up without much effort thanks to plug-and-play and are suitable in the enterprise sector for networking IP-based surveillance cameras. When it comes to smaller networks where the user base remains small and configuration and management need less attention, unmanaged switches are an ideal and cost-effective solution. 

In the event of a power failure, the UPS (uninterruptible power supply) ensures that IT systems in companies still have power available for a limited period of time. Especially in today's age of automation, it is essential for companies to always ensure that the entire IT infrastructure functions without interruption. The UPS therefore aims to keep operations running (also called business continuity). The UPS is also important in data protection, because in the event of a power failure, data could be lost that cannot be recovered. In most cases, UPS systems are used in conjunction with mains backup systems. 

Voice over IP (VoIP), also known as VoIP telephony, IP telephony or Internet telephony, describes the transmission of telephone calls over the Internet. VoIP enables telephony between computers, tablets and smartphones with Internet access without the need for a stationary telephone or a special telephone system as a starting point. A broadband Internet connection can be used to transmit several calls and their voice signals in parallel via an IP network, and the telephone systems from several locations can be linked together. For example, it is possible for an employee who works from home in Magdeburg to make calls using a landline number from the company's headquarters, e.g. a Berlin landline number. 

The virtual server is also known as the virtual machine (VM). The virtual server is a software that runs on a physical server and behaves like it but only exists virtually. The physically present server can have multiple, virtual servers. Virtual servers provide resources such as memory, hard disks, and the CPU and are mostly used for testing new operating systems, software or other unknown files, as virtual servers provide a secured environment. They are a cost-effective alternative for businesses as they do not require maintenance and save power. 

A virus or computer virus ensures that software is manipulated, and thus great damage is caused. In this context, the term computer virus is derived from the virus of medicine. The computer virus behaves like the medical virus in that it installs harmful parts - in this case harmful software - on the affected system and damages it or, in the worst case, destroys it. In the process, the computer virus can also spread and thus damage or infect other systems. Computer viruses infiltrate software, operating systems, RAM, or boot sectors in order to have a destructive effect. The term computer virus also includes malware, Trojans, and computer worms. 

The term VPN means "virtual private network". With the help of a VPN connection, a secure connection can be established between one's own computer and the Internet. The secure connection ensures that data traffic via the VPN is anonymized, and the online identity is concealed. For this purpose, the own IP address is hidden. This is advantageous, among other things, when public WLAN hotspots are used. In companies, for example, a VPN is used when employees in the home office need to be securely connected to the company network. Without a VPN, data is processed via the respective Internet service provider. The VPN is a type of tunnel in which data traffic flows through a VPN server. The VPN changes the IP address, disguises the location, encrypts the data, and thus protects against unauthorized access or tapping of the data. 

The Virtual Router Redundancy Protocol, VRRP for short, is a procedure developed in 1998. In this procedure, redundant routers are used to increase the availability of important gateways in local networks. The redundant gateway routers form a group and a virtual router is set up. The virtual router is equipped with its own IP or MAC address. All data runs through the imaginary router. If the network is heavily loaded, VRRP uses backup routers as load distributors. These prevent the master router from failing. If, nevertheless, a connection loss or failure is imminent, the incoming and outgoing data streams are redistributed to the remaining backup routers. The VRRP thus offers fail-safe data paths. 

WAN: 

WAN, a wide area network, is a large network that connects multiple LANs or computer systems together. The connection can extend over a large geographical distance, for example across countries or continents. The WAN differs from WLAN, LAN or MAN, all of which are intended for a smaller geographical distance. Wide area networks are often used by Internet service providers to allow users to access the Internet. WANs are used within companies, for example to offer in-house cloud systems or to connect networks from different locations. 

The abbreviation WLAN stands for Wireless Local Area Network and describes a wireless, local connection to the Internet. The so-called wireless network often forms the basis of a home network in the private and business sectors and, to put it simply, provides the devices connected to it with Internet access. In order to be able to set up a WLAN, a WLAN router is required, which converts the local Internet into a wireless network. The WLAN is limited to a small local area, but can be expanded as required with access points or WLAN repeaters. 

Web application control controls what end users can and cannot do on a server or in enterprise applications. Web application control can reduce the risk of malware, or zero-day exploits being introduced. While blocking access can ensure that productivity is reduced, it conversely provides greater security and thus keeps the risk of downtime low. In addition, web application control can prevent license compliance regulations from being ignored. For example, Web application control can be used to specify that users can only use a single Web browser. 

An XFP module is a 10 Gigabit Small Form-Factor Pluggable module. XFP is a standard for transceivers and in high-speed networks and telecommunications connections. Optical fibers or fiber optic cables are used. XFP has a slightly larger form factor than the popular small form factor pluggable transceivers SFP as well as SFP+. XFP modules can be hot-swapped. Most commonly, XFP modules operate in near-infrared wavelengths between 850 nm and 1550 nm. Because XFP modules use an LC fiber connector type, they achieve higher density. Among others, 10 Gigabit Ethernet applications use XFP modules. 

YaST ("Yet another Setup Tool") is the installation and configuration tool for openSUSE as well as SUSE Linux Enterprise distributions. The YaST tool is used to administer the Linux system. It consists of different YaST modules. YaST consists of the installation wizard and the YaST control center. Thus, YaST is the central hub for installing software, setting up hardware, configuring Internet access, and managing other important tasks under Linux. Normally, the YaST tool is available as a graphical user interface. Alternatively, it can also be administered via a text mode or the command line via SSH connection. Admin rights are required to access the individual configuration modules of the YaST tool. 

A zero-day exploit is a bug in software or hardware that can lead to major problems. The problem with the zero-day exploit is that it is difficult to detect. The term zero day itself means that hackers discover new vulnerabilities and then attack the affected systems. Here, zero day refers to the day when the manufacturer or developer learns that a flaw exists and has zero days to fix it. Therefore, the zero-day attack is the day hackers attack because the manufacturer or developer has not yet had time to fix the vulnerability. Zero-day exploits therefore affect operating systems, web browsers, office applications, and hardware and firmware, among others.