15 Different Types of Servers in Computing PDF

15 Different Types of Servers in Computing A server is a computer program or equipment that offers a service to another computer program and its users, referred to collectively as the clients. The physical system that a server program runs on is sometimes referred to as a server in a data center. Th...

15 Different Types of Servers in Computing A server is a computer program or equipment that offers a service to another computer program and its users, referred to collectively as the clients. The physical system that a server program runs on is sometimes referred to as a server in a data center. That machine may be a dedicated server, or it could be utilized for anything else. In a client/server programming architecture, a server program waits for requests from client programs, which could be running on the same machine or on a different one. One program on a computer can act as both a client and a server when other programs ask for its services. The usage of servers may be defined as providing data to users. Servers can be used to manage a network, share files or programs, host databases, and host web pages and e-mail. The server is similar to personal computers. Its components are the processor (CPU), memory (RAM), and hard disk. Servers contain hardware and programs that are tailored to their intended function. As a result, the target server type is determined by the intended purpose. In this article, we will outline the most prevalent types of servers used today. The most widely used types of servers are as follows: 1. Web Server 2. Database Server 3. Email Server 4. Web Proxy Server 5. DNS Server 6. FTP Server 7. File Server 8. DHCP Server 9. Cloud Server 10. Application Server 11. Print Server 12. NTP Server 13. Radius Server 14. Syslog Server  15. Physical Server Figure 1. Types of Servers 1. Web Server The server that is in charge of publishing a website on the internet is known as a web server. A server that provides hosting, also called "hosting", over the internet protocol is called a web server. The renting of space required to publish Web pages on the Internet is referred to as "hosting". Hosting means putting pages, images, or documents meant for a website on a computer that internet users use to access them. Apache, Microsoft's Internet Information Server (IIS), and Nginx are the most popular web servers on the Internet. The data for each site you see on the internet is stored on another host, and software called Web Server. Web Server is used to efficiently use this computer. Web servers are typically made up of numerous software packages. Each of these software packages aids in the control of various functions. For example, the File Transfer Protocol (FTP) package that comes with web server software helps the server do FTP tasks. Similarly, numerous packages are available to perform a variety of tasks, such as serving emails, fulfilling download requests, and publishing web pages over HTTP. The most common web servers are as follows:   Apache HTTP Server: The Apache Software Foundation created the world's most popular web server. Apache is an open-source web server that can be installed on Linux, Unix, Windows, FreeBSD, Mac OS X, and many other operating systems. The Apache Web Server is used by over 60% of web server computers.  Internet Information Services: Microsoft's Internet Information Server (IIS) is a high-performance Web server.  Lighttpd: Lighttpd, pronounced lighty, is a free web server that comes with the FreeBSD operating system. This open-source web server is quick, safe, and uses far less CPU power. Lighttpd may also be run on Windows, Mac OS X, Linux, and Solaris.  Nginx: Nginx Web Server is a critical component in the client-server computing environment, providing business-critical information to client systems. Like Lighttpd, it is an open-source web server that is known for being fast and needing few resources and time to set up. It is mostly used for caching, streaming media, load balancing, managing static files, auto-indexing, and other similar tasks. Nginx handles requests on a single thread, employing an asynchronous technique rather than generating new processes for each request made by the user.  Sun Java System Web Server: Sun Microsystems' web server is designed for medium and large websites. The server is free, but it is not open source. It, on the other hand, runs on Windows, Linux, and Unix platforms. The Sun Java System web server supports a wide range of Web 2.0 languages, scripts, and technologies, including JSP, Java Servlets, PHP, Perl, Python, Ruby on Rails, ASP, and Coldfusion. 2. Database Server A database server manages a database and provides database services to clients. The server manages data access and retrieval as well as the completion of client requests. A database server is a computer that runs database software and is dedicated to providing database services. A database server is made up of hardware and software that is used to run a database. Database servers have a variety of applications. Among them are:  Dealing with large amounts of data regularly. Database servers shine in client-server architectures where clients process data frequently.   Managing the DBMS's (database management system) recovery and security. Database servers enforce the constraints specified in the DBMS. The server manages and controls all clients connected to it, as well as all database access and control requests.  Concurrent access control is provided. Database servers provide a multi-user environment in which multiple users can access the database at the same time while maintaining security and concealing the DBMS from clients.  Application and non-database file storage Database servers are a much more efficient solution for some organizations than file servers. Most database servers use the client-server model. They get requests from client devices and their users and then send back the response that was asked for. Database servers are powerful machines that can connect to multiple databases and serve resources to clients, sometimes with the help of application servers and web servers that act as middlemen. Databases, for example, can provide resources to clients in the absence of a web or application server (usually on-premises). What are the Database Server Examples? Here are a few well-known examples of database servers.  Oracle: Oracle is the most commonly used database for object- relational database administration, and the most recent version is 12c (12 Cloud Computing). It supports various Linux, Windows, and UNIX versions.  IBM DB2: IBM DB2 was designed in C, C++, and Assembly and was initially released in 1983. Its setup and installation procedures are straightforward, as is data access. As a result, it aids in the storing of large volumes of data, up to petabytes.  Microsoft SQL Server: This server was first introduced in 1989. It is written in several languages, including Assembly, C, Linux, and C++. It can run Linux and Windows. It enables multiple users to use the same database at the same time.  MySQL: MySQL is becoming more popular for many web-based applications. It is available as both a freeware and a premium edition.  SAP HANA: It was created by SAP SE and can manage both SAP and non-SAP data. It is capable of supporting OLTP, OLAP, and SQL. It can communicate with a wide range of different apps.   MS Access: It is only compatible with Microsoft Windows. Because this database management system is inexpensive, it is commonly used for e-commerce websites. 3. Email Server A mail server, also known as an email server, is a computer system that sends and receives emails. When you send an email, it passes through several servers before arriving at its destination. While this process is quick and efficient, there is a significant amount of complexity involved in sending and receiving emails. For a computer to work as a mail server, mail server software must be installed on it. The system administrator then uses this software to create and manage email accounts for any of the domains hosted on the server. Aside from that, you have protocols. Protocols are network software rules that enable computers to connect to networks from anywhere, allowing you to shop online, send emails, and so on. Mail servers are classified into two types: outgoing mail servers and incoming mail servers. SMTP, or Simple Messages Transfer Protocol, servers handle outgoing mail. Incoming mail servers are classified into two groups. Messages are kept on the server while using IMAP. When using POP3, messages are often stored on a device, such as your computer or mobile phone. IMAP, in general, is more complicated and adaptable than POP3.  SMTP: The SMTP protocol handles all incoming mail and sends emails. SMTP stands for Simple Mail Transfer Protocol and refers to the outgoing mail server. Consider SMTP to be the transport of your email across networks. Your emails would be useless without them.  IMAP / POP: There are two types of incoming mail servers-POP3 and IMAP. Post Office Protocol version 3 (POP3) servers are well-known for getting your computer's Inbox contents. IMAP servers, which stand for Internet Message Access Protocol, are used for one-way mailbox synchronization. IMAP is used as an additional protocol retrieval application on a mail server. And, while there are newer POP versions with more functionality, the recommended protocol remains POP3 since it is straightforward, has a high success rate, and gets the job done with the fewest problems. You can even download your emails and read them offline. Your email would not reach your machine if one of these protocols was not functioning properly. How Email Server Works A mail server, in its most basic form, collects email and forwards it to its intended recipients. It can be thought of as a computer serving as an e-mail office, allowing control of e-mail transmission over a network using various protocols. How an e-mail server works are explained below: 1. Making a connection to the SMTP server: When you send an email, your email service or provider will connect to the SMTP server, such as Gmail, Exchange, Office 365, Expert Mail, or Zimbra. This SMTP server is associated with your domain and has a unique address. At this point, your email provider will send crucial information to the SMTP server, such as your email address, message body, and recipient's email address. 2. Taking care of the recipient's email domain: The SMTP server identifies and processes the recipient's email address in this phase. If you email someone else within your firm, the message will be sent directly to the IMAP or POP3 server. If you are sending the message to another company, the SMTP server must speak with the email server of that company. 3. Determining the IP address of the recipient: At this point, your SMTP server needs to connect to the recipient's server using DNS (Domain Name System). DNS functions similarly to a translation mechanism. It aids in the conversion of the recipient's domain name into an IP address. To function effectively, SMTP requires an IP address to forward the message to the recipient's server. 4. Email delivery: Everything is not as straightforward as it appears. In general, your email will be routed through several SMTP servers before arriving at the recipient's SMTP server. When the recipient receives the email, SMTP validates it before forwarding it to the IMAP or POP3 server. The email is then processed in a queue until it is available for the recipient to access. 4. Web Proxy Server People rarely consider how complicated the internet is. The threat of crimes such as identity theft and data security breaches is growing. To protect themselves, many people employ proxy servers or Virtual Private Networks (VPN). A proxy server is a web server that serves as a conduit between a client program, such as a browser, and the actual server. It sends queries to the accurate server on the client's behalf and sometimes fulfills the claim itself. Web proxy servers offer two key functions: they filter requests and increase performance. In addition, there are reverse proxy servers that reside between web servers and web clients. Requests from web clients are routed through reverse proxy servers to web servers. They are used to cache pictures and pages to drastically minimize the strain on web servers. There are various reasons why an individual or company may use web proxy servers. Limit internet access. You can control and keep an eye on your kids' internet use as an individual by using proxy servers. It operates by blocking undesirable websites and preventing access to pornographic content. Proxy servers are also used by businesses to block and regulate internet access. They use this to keep employees from surfing the web while at work. Alternatively, they track all web requests, which shows which websites employees visit and how much time they spend online. Benefits of using a web proxy server are as follows:  More privacy: By altering your IP address and other identifying data on your computer, proxy servers allow you to access the internet more discreetly. Proxy servers protect your personal information, so the server does not know who made the request, keeping your surfing activity and browser history secret.  Access to restricted websites: Material providers restricts their content for a variety of reasons, including location, which is effectively the IP addresses. A web proxy server, on the other hand, allows you to log on to a restricted service by making it appear that you are at a different location.  Improved performance and bandwidth savings: Using effective web proxy servers, businesses may save bandwidth and increase loading rates. To preserve the most recent copy of a website, proxy servers cache pictures and web data. Caches enable a proxy server to obtain the most recent copy of popular sites, saving traffic and improving network efficiency.  Enhanced Security: Efficient proxy servers encrypt your online requests to keep them safe from prying eyes and to safeguard your transactions. Proxy servers are used to avoid attacks from known malware sites. VPNs are also used by businesses to boost security and allow remote users to access the company network. Web proxy servers are important in cybersecurity for both individuals and organizations. What are the Best Web Proxy Servers? The most popular and greatest web proxy servers are as follows:  SmartProxy: Best for quickly configuring proxies in Firefox and Chrome. Smartproxy provides a home proxy network that allows you to send an infinite number of connection requests at the same time. This  enables your scraper to quickly visit a large number of web pages. You can create a different proxy user for each job. Each of these proxy users will have their login information. This service makes it extremely simple to set up proxies. Smartproxy provides extensive documentation that covers everything you'll need to know about setting up and installing proxies.  Bright Data: Ideal for creating data-driven business decisions since it aids in the unlocking of any website and the collection of reliable data. Bright Data includes a Proxy Manager that allows you to manage all of your proxies from a single interface. The Proxy Manager is a free and open-source application. It includes scraping capabilities. Bright Data provides Data Center Proxies, ISP Proxies, Residential Proxies, Mobile Proxies, Web Unlocker, and other solutions.  HMA: Best for browsing anonymously. For anonymous browsing, HMA offers a free proxy server. It enables access to banned websites from anywhere in the world and includes features like private browsing in a single tab, IP masking in a single tab, and safe online banking on any network, among others. We may use it on any device, making online games and apps safer.  Whoer: The best tool for fast-changing IP addresses and unblocking websites for free. Whoer provides web proxy, Internet speed testing, online ping test checker, domain & IP verification, and DNS leak testing services. Its web proxy provides a quick and free solution to change your IP address, unblock websites, and acquire web anonymity. Services are available in various countries.  Hide.me: The best VPN for speed and privacy protection. Hide.me is a web proxy service that offers apps for all platforms as well as secure VPN protocols. It adheres to a stringent no-logs policy. The premium edition includes dynamic port forwarding, a fixed IP address, and streaming capability. It offers a free browser extension for Firefox and Chrome. 5. DNS Server The Domain Name System (DNS) is the Internet's telephone directory. DNS is responsible for finding the correct IP address for websites when users enter their domain names, such as 'google.com' or 'nytimes.com,' into web browsers. The addresses are then used by browsers to communicate with origin servers or CDN edge servers to access website information. All this is possible by DNS servers, which are specialized machines for answering DNS queries. To resolve names, the DNS system has resolving systems. Name resolvers are used to find IP addresses associated with domain names. DNS clients are the people who use resolvers. A DNS system can have many name resolvers. As a result, if one of them becomes incapacitated, the others take over and ensure that communication is not disrupted. When you type a domain name into your browser and log in, your browser first asks your operating system for the domain name, which does not answer. Then it asks your modem and continues to ask until it reaches the Internet service provider and the main DNS servers. If the matching DNS server database contains an equivalent of this domain name, it will respond to the IP address, and your browser will get this response in a fraction of a second and speak with the server where the relevant domain name is hosted. The data transfer then begins, and the required webpage is displayed in your browser. In an uncached DNS query, four servers collaborate to supply an IP address to the client: recursive resolvers, root nameservers, TLD nameservers, and authoritative nameservers. The DNS recursor (also called the DNS resolver) is a server that accepts the DNS client's query and then contacts other DNS servers to locate the proper IP address. When the resolver receives the client's request, it acts like a client, contacting the other three types of DNS servers in search of the correct IP address. The resolver begins by querying the root nameserver. The root server is the first step in converting human- readable names to IP addresses (resolving). The root server then responds to the resolver by supplying the address of a top-level domain (TLD) DNS server (such as.com or.net) that includes data for its domains. 6. FTP Server FTP is a network protocol that is used to transfer files between a client and a server on a computer network. FTP is a well-known protocol that was developed in the 1970s to allow two computers to transfer data over the internet. One computer serves as the server, storing information, while the other serves as the client, sending or requesting files from the server. The FTP protocol's primary mode of communication is normally port 21. On port 21, an FTP server will accept client connections. FTP servers, as well as the more secure SFTP Server software, carry out two basic functions: "Put" and "Get." An FTP Server is useful if you have remote employees who need to submit non-confidential material (such as timesheets), or if you wish to allow your clients to obtain white papers and documentation. If you're transferring non- sensitive data with a business partner who requires FTP or SFTP, you can rapidly set up a server to accept their data transfer. Some people even utilize FTP servers for offsite backup so they can access their data if something happens to their files physically. Furthermore, backup apps frequently write to an FTP or SFTP Server; for example, if you are backing up your Cisco Unified Call Manager (CUCM), the data must be backed up to an SFTP Server, such as Titan FTP Server. FTP Server is defined as an infrastructure that enables organizations with various file transmission options. FTP servers, which have numerous advantages in this regard, are particularly appealing to organizations looking to enhance their multimedia experience. In addition to options such as quick file transmission and integrated usage options, the following are the highlights of FTP server advantages:  Options for Effective File Sharing: Businesses that put up FTP infrastructure speed up file transfer between business machines via their clients. Devices have multimedia capabilities that allow them to communicate efficiently with one another. As a result, needless data transfer stages are disabled.  Providing Data Security: Because FTP performs all data transfer activities through the in-house client, it also protects against outside cybersecurity breaches. The fact that the client in the company communicates with the company devices across the common network also aids in isolating the network from external variables.  Interaction across a Common Network: Another significant benefit of an FTP server for organizations is that it enables devices to connect in an integrated manner across a single network. As a result, the company's gadgets can communicate indefinitely with the client. As a result, communication between company devices continues at its peak. 7. File Server A file server is a central server in a computer network that serves file systems or portions of file systems to clients connected to the network. As a result, file servers provide users with a central storage location for files on internal data media that is available to all authorized clients. The server administrator establishes rigorous guidelines for which users have which access rights: For example, the configuration or file authorizations of the individual file system allow the admin to specify which files a certain user or user group may access and open, as well as whether data can only be seen or additionally added, altered, or deleted. Users can access files over the local network as well as remotely when file servers are linked to the internet and set up properly. This allows users to view and store files on the file server when they are on the move. All current operating systems, such as Windows, Linux, or macOS, can be used on a file server, but the network devices must be compatible with the operating system. However, file servers are used for more than just file storage and administration. They are also frequently used as a backup server and as a repository for applications that must be available to numerous network members. Clients can only access a distant file system through file servers. They can hold any form of material, such as executables, documents, images, or movies. They typically store data as binary blobs or files. This implies they don't do any further indexing or processing on the files they store. However, there may be other plugins or server operations that can give additional functionalities. A file server does not have built-in methods for interacting with data and relies on the client to do so. Because databases only deal with structured data that is retrieved via a query, they are not considered file servers. File servers usually incorporate extra capabilities that allow several users to use them at the same time: Permission management is used to control who has access to certain files and who has the authority to alter or delete them. Locking a file prevents several people from editing the same file at the same time. Resolution of conflicts; preservation of data integrity in the case of file overwriting. By duplicating data to numerous servers in different places, a distributed file system may make data redundant and highly accessible. For many businesses, employing a file server is worthwhile for a variety of reasons. The first advantage is, obviously, centrality, which assures that any authorized network participant has access to the stored data. This enables collaborative work on certain files. Conflicts between multiple versions of a document may be virtually eliminated since certain operations, such as editing or deleting, are disabled for other users as soon as you access a file. If users have to share the needed files on their system or send them via removable media, it will be significantly more time-consuming and inconvenient - and it will almost certainly result in different file versions. Another significant benefit of employing file servers is that it alleviates the burden on client resources. Except for personal papers, almost all corporate data and backups can be saved on the file server, depending on how the organization intends to use the file repository. And, with the proper arrangement (directories, folders, etc.), users get a far better perspective of the full file inventory. If the file server is set up for remote access through the internet, the files are also available on the go, similar to an online storage service. Unlike cloud service, however, the organization maintains complete control over the files and their security at all times. This is a significant benefit over third-party solutions. 8. DHCP Server A DHCP Server is a network server that gives and assigns IP addresses, default gateways, and other network information to client devices on an automatic basis. To reply to client broadcast inquiries, it uses the standard protocol known as Dynamic Host Configuration Protocol or DHCP. A DHCP server automatically sends the network parameters required for clients to communicate successfully on the network. Without it, the network administrator must manually configure each client that connects to the network, which can be time-consuming, especially in big networks. DHCP servers typically assign a unique dynamic IP address to each client, which changes when the client's lease for that IP address expires. Each device connected to the Internet on an IP network must be allocated a unique IP address. DHCP allows network managers to centrally monitor and assign IP addresses. When a computer is relocated, it can automatically give a new IP address to it. DHCP automates the process of allocating IP addresses, reducing both the time necessary for device configuration and deployment and the likelihood of configuration errors. A DHCP server can also manage the setups of several network segments. When a network segment's configuration changes, an administrator merely needs to update the relevant settings on the DHCP server. Configuration of a dependable IP address. DHCP reduces manual IP address configuration problems, such as typographical errors, and address conflicts caused by assigning an IP address to more than one computer at the same time. Network administration has been simplified. To reduce network administration, DHCP supports the following features:  TCP/IP configuration is centralized and automated. The ability to define TCP/IP setups from a single point of contact.  The ability to use DHCP to assign a wide variety of additional TCP/IP configuration parameters. The efficient management of IP address changes for clients that need to be updated often, such as portable devices that roam across a wireless network. 9. Cloud Server A cloud server is a pooled, centralized server resource that is hosted and distributed across a network -typically the Internet- and may be accessed by multiple users on demand. Cloud servers provide all of the same services as traditional physical servers, including processing power, storage, and applications. Cloud servers can be situated anywhere in the world and provide remote services via a cloud computing environment. Traditional dedicated server hardware, on the other hand, is often installed on premises for the sole use of one firm. Because any software issue is isolated from your environment, a cloud server is used. Other cloud servers will have no impact on yours, and vice versa. In contrast to physical servers, another user overloading their cloud server does not influence your cloud server. Cloud servers are dependable, fast, and secure. Because they do not have the hardware issues that physical servers do, they are likely to be the most stable alternative for firms that want to keep their IT expenditure as low as possible. Cloud servers provide greater service at a lower cost. You'll get more resources and faster service than you would with an equivalent physical server. It is relatively simple and quick to upgrade by adding memory and storage space, and it is also less expensive. 10. Application Server An application server is software that runs on the server and is written by a server programmer to provide business logic for any application. This server might be part of a network or a dispersed network. Server programs are typically used to give services to client programs that are either on the same system or a network. Application servers reduce traffic while increasing security. It is not possible to achieve ideal web server agility by handling both HTTP requests from web clients and passing or storing resources from numerous websites. Application servers fill this need with a powerful architecture designed to handle dynamic online content requests. Application servers provide programs with protection and redundancy. The task of conserving and replicating application architecture across the network becomes more achievable once deployed between a database and a web server. The extra step between potentially harmful web connections and the database server's crown jewels offers an extra degree of security. Because application servers can handle business logic queries, an attempted SQL injection is more difficult. Some of the advantages of Application Servers can be listed as follows:   Provides a framework for managing all components and operating services such as session management and synchronous and asynchronous client notifications. It becomes incredibly simple to install programs in one location.  Any configuration change, such as changing the Database server, may be made centrally from a single place. They make it simple to deliver patches and security upgrades.  It allows you to route requests to other servers based on their availability. Load balancing is used to accomplish this.  It ensures the security of applications. It allows for fault tolerance as well as recovery/failover recovery.  It saves us a lot of time if we have to install a duplicate of settings on each machine manually. It has transaction support.  Because it is built on the client-server concept, the application server dramatically enhances application performance. 11. Print Server A print server is a software program, network device, or computer that manages print requests and provides end users and network administrators with printer queue status information. Print servers are used in big business networks as well as small or home office (SOHO) networks. A single dedicated computer operating as a print server in a large firm manages hundreds of printers. A print server in a small office is generally a customized plug-in board or tiny network device the size of a hub that serves the same function as a dedicated print server while freeing up critical disk space on the workplace's limited number of PCs. A print server, like other servers, works on the client-server architecture, receiving and processing user requests. Physical print servers, as shown in the diagram above, sit on the back end of an organization's network and connect directly to network printers, retaining control over the print queue. The print server handles devices to request information, such as file and print requirements. While most printing occurs within workplace networks, print servers are available to external network clients (typically via approved login). Print-server software can be deployed on a network file server or your computer. UNIX-based operating systems such as Mac OS X and Linux, by default, employ the CUPS, or Common UNIX Printing System, which includes built-in print-server functionality. A print server can also be a single-purpose network hardware device that connects to a printer directly. Some printers include print-server technology that allows them to connect directly to a network router or switch. There are several ways to connect a printer to a print server. It might be physically linked to a file server or client computer by a parallel, serial, or USB connection. Dedicated network print-server hardware devices connect to a printer directly through a parallel or USB connection and the network wirelessly or by an RJ45, Ethernet cable connection. Printers with built-in print-server hardware can connect to the network through wireless or Ethernet. Before your document is finally printed and ready for pickup, the print server, and your computer's operating system must locate the printer you want to use, establish a network communication path to it, package your document into a data format that the printer can directly understand, send the formatted data to the printer, and monitor the printer's progress as it prints your document. Finally, it informs you whether or not the printing procedure was successful. The printer drivers installed on your computer, as well as network printing protocols such as IPP (Internet Printing Protocol) and LPR (Line Printer Remote protocol), manage the complex, low-level details for you. While printers are slower output devices than hard drives or CD writers, print-server software may compensate by keeping your document in a temporary file called a spool and only sending out bits of your document at the pace at which your printer can reliably handle them. If you send numerous documents to the printer or if many users try to print at the same time, print servers installed on network file servers can queue each page. The printer server transmits documents in the queue to the printer in a systematic, dependable, first-come, first-served manner. 12. NTP Server Network Time Protocol (NTP) is an internet protocol that is used to synchronize with computer clock time sources in a network. It belongs to and is one of the earliest components of the TCP/IP suite. The word NTP refers to both the protocol and the client-server applications that operate on computers. NTP was invented in 1981 by David Mills, a professor at the University of Delaware. It is intended to be extremely fault-tolerant and scalable, while also allowing temporal synchronization. The NTP time synchronization procedure consists of three steps: 1. The NTP client conducts a time-request exchange with the NTP server.  2. The client may then determine the connection latency and its local offset, as well as change its local time to match the clock on the server's computer. 3. Typically, six exchanges over a five to ten-minute period are required to set the clock. Once synced, the client refreshes the clock approximately every 10 minutes, needing only a single message exchange in addition to client-server synchronization. This transaction takes place on port 123 of the User Datagram Protocol (UDP). NTP also provides peer computer clock broadcast synchronization. Accurate time for all devices on a computer network is critical for several reasons; even a fraction of a second difference can cause problems. The following are some instances of how NTP is used:  Coordinated times are required for distributed procedures to guarantee proper sequences are followed.  Consistent timekeeping across the network is required for security procedures.  File system changes performed across several machines rely on synchronized clock times.  To monitor performance and fix issues, network acceleration and network management systems rely on the precision of timestamps. 13. Radius Server RADIUS (Remote Authentication Dial-In User Service) is a networking protocol that connects clients and servers. RADIUS is a computer network authentication, authorization, and accounting (AAA) management protocol. RADIUS is a UDP-based protocol that authenticates users using a shared secret. The RADIUS protocol employs a RADIUS Server and RADIUS Clients.  RADIUS server: checks users' credentials against a database of usernames and passwords. It also grants network resources access.  RADIUS client: a network-connected device that provides its credentials to the RADIUS server. After that, the RADIUS server authenticates the client and returns authorization or access control information to it. To establish an authenticated session, the RADIUS  server, and client exchange messages. This session is used for duties such as authorization, bookkeeping, and others. To authenticate remote users, a RADIUS server consults a central database. When access is allowed, RADIUS acts as a client-server protocol, authenticating each user with a unique encryption key. The particular nature of the RADIUS ecosystem determines how a RADIUS server operates. An overview of RADIUS servers is provided below. 1. First, the user authenticates with the network access server (NAS). 2. The network access server will then request a username and password or a challenge (CHAP). 3. The user responds. 4. When the RADIUS client receives the user's response, it sends the username and the uniquely encrypted password to the RADIUS server. 5. The user is accepted or rejected by the RADIUS server. RADIUS servers are well known for their AAA (Authentication, Authorization, and Accounting) capabilities. The key benefits of a RADIUS server's centralized AAA capabilities are increased security and efficiency. RADIUS servers enable each firm to protect the privacy and security of both the system and each user. RADIUS Authentication Methods The RADIUS server offers a variety of authentication techniques. When supplied with the user's username and original password, it can support PAP, CHAP, MS-CHAP, EAP, EAP TLS, UNIX login, and other authentication protocols.  PAP: Password Authentication Protocol (PAP) authentication configures authentication using PPP configuration files and the PAP database. PAP works similarly to the UNIX login software, however, PAP does not allow the user shell access.  CHAP: Challenge-Handshake Authentication Protocol (CHAP) authentication employs challenge and response, which means that the authenticator challenges the caller (authenticates) to prove their identity. The challenge includes the authenticator's unique ID and a random number. The caller generates the answer (handshake) to send to the peer using the ID, random number, and CHAP security credentials.   MS-CHAP: MS-CHAP is the Microsoft Challenge-Handshake Authentication Protocol (CHAP). It is used as an authentication option in Microsoft's PPTP protocol implementation for VPNs.  EAP: Extensible Authentication Protocol (EAP) is a wireless network and point-to-point connection authentication mechanism. 14. Syslog Server The System Logging Protocol (Syslog) is a standard message format used by network devices to connect with a logging server. It was created primarily to make monitoring network devices simple. Devices can use a Syslog agent to send out notification messages under a variety of scenarios. These log messages comprise a timestamp, a severity rating, a device ID (including IP address), and event-specific information. Though it has flaws, the Syslog protocol is extensively used because it is simple to construct and very open-ended, allowing for a variety of proprietary implementations and hence the ability to monitor practically any connected device. The Syslog standard specifies three layers:  Syslog Content Layer: This is the content in the event message. It includes several data items such as facility codes and severity ratings.  Syslog Application Layer: The message is generated, interpreted, routed, and stored in this layer.  Syslog Transport Layer: This layer is responsible for sending messages across a network. When debugging difficulties, log information is quite useful. For example, if some users report a network outage, such as the recent Facebook, WhatsApp, and Instagram outages, we can simply scan through all of the log data to check if there were any difficulties. Data retention is another advantage of centrally keeping log information. It can give temporary information required to restore the system's previous status after a failure. Syslog messages are transmitted through User Datagram Protocol (UDP) port 514. Because UDP is a connectionless protocol, messages are neither acknowledged nor guaranteed to arrive. This can be a disadvantage, but it also makes the system basic and easy to manage. Syslog messages are frequently in human-readable format, but they do not have to be. Each message has a priority level in its header, which is a mix of code for the process of the device creating the message and a severity level. The process codes, known as "facilities," are based on UNIX. Severity levels vary from 0 (emergency) to 1 (urgent attention required), with informational and debug messages falling somewhere in between. These two codes, when combined, enable rapid classification of Syslog messages. 15. Physical Server Some servers are solely utilized for specific functions. An application server, for example, just hosts the webpage. Physical servers are easy to use for a wide range of network tasks because of their software and hardware. Some of those transactions are:  Operating system updates  Services for firewalls  Anti-spam software  Antivirus software  Defense against DDoS assaults  DNS hosting  Intrusion detection  SNMP management  Database administration  Backups and restoration  Security Procedures