dns defination

When two human talks to each other, they may have to use the same language but they generally understand each other without having to adhere to rigid rules of grammar or formal language frameworks. Computers, on the other hand, have everything openly defined and structured. If computers wish to communicate with another one, they have to know in advance exactly how information is to be exchanged and precisely what the format will be.

Therefore, standard methods of transmitting and processing various kinds of information are used and these methods are called “Network Protocol“. Protocols are established by international agreement and ensure that computers everywhere can talk to one another. There are many network protocol for different kinds of information and functions.

Network protocol is similar to programming languages, based on specific rules and regulations for computing and efficiency. Each rule is defined in different terms and assigned a unique protocol name. Network Protocol identifies the standards for communication and provides detailed information on processes involved in data transmission. Such processes include:

• Type of the task
• Nature
• Rate of Data flow
• Type of Data flowing
• Device management

A single data sending process can be handled using more than one network protocol. This coordination of network protocols creates a network protocol family. The important and well-known network protocol are :

Telnet (TN)

Telnet (TN) is an important network protocol used to access remote host resources over the Internet or a TCP/IP computer network. It stands for Teletype Network and used to establish a remote connection using the telnet protocol. Telnet was established in 1969 and standardized as one of the first Internet standards by the Internet Engineering Task Force (IETF) for remote connection.

A host (Telnet server), runs a telnet server application (or daemon in Unix terms) that receives a connection from a remote host called the telnet client. The connection is presented to the operating system of the telnet server as though it is a terminal connection connected directly. Telnet provides a text-based software providing access to the command line interface of the host computer.

Note:- Do not confuse the telnet application with the Telnet protocol. Telnet is an application layer protocol.

HTTP

Http stands for HyperText Transfer Protocol. It is an application layer protocol and the foundation of the World Wide Web. HTTP is used for transferring files like graphic images, sound, video, text and other multimedia files on the web. It also defines how messages are formatted and transmitted; and what actions Web servers and browsers should take in response to different commands.

HTTP transfer Web pages and such resources from the Web Server to the Web Client using different types of a web browser such as Internet Explorer, Google Chrome or Firefox. For example, when someone enters a URL in their web browser, this actually sends an HTTP command to the Web server directing it to get and transmit the requested Web page.

HTTPS

Hypertext Transfer Protocol Secure is the advance and secure version of the Hypertext Transfer Protocol (HTTP). It is used for secure transfer of data over a computer network and is widely used on the Internet. The “S” in HTTPS stands for “Secure”. It looks as illustrated in the image below, the lock icon in the address bar of the web browser.

File Transfer Protocol (FTP)

FTP is a standard protocol for transferring files between computers on the Internet over TCP/IP connections. It provides a method for copying files over a network from one computer to another computer. It is a client-server protocol that relies on two communications channels between client and server generally. Clients start conversations with servers requesting to download a file. Using FTP, a client can upload, download, delete, rename, move and copy files on a server. A user classically needs to log on to the FTP server, although some servers make some or all of their content available without login, also known as anonymous FTP.

FTP provides some simple file management on the contents of a remote computer. It is an old protocol; used less than it was before the World Wide Web came along. Nowadays, its main usage is to upload files to a Web site. Sites that have a lot of downloading like software sites often have an FTP server to handle the traffic. If FTP is involved, the URL will have FTP at the front.

TFTP

TFTP stands for Trivial File Transfer Protocol and it is the simplest version of FTP. Where FTP allows a user to see a directory listing and perform some directory related functions and also provide user authentication. TFTP is a small and fast protocol allows sending and receiving of files without user authentication. Due to this inherent security risk, it is not widely used. Trivial File Transfer Protocol (TFTP) uses the User Datagram Protocol (UDP) rather than the Transmission Control Protocol (TCP).

SMTP

It is the standard protocol for email services on a TCP/IP network and provides the ability to send and receive email messages. SMTP is an application layer protocol enables the transmission and delivery of email over the Internet. The IETF created SMTP and they also maintain it.

The SMTP is also between two emails servers to send and receive emails. However, the end client does not receive emails using SMTP. The end clients use the POP3 protocol to do that. SMTP also known as RFC 821 and RFC 2821.

DNS

Every host in a network has a logical address called the IP address. These addresses are a bunch of numbers. When you go to a website such as https://networkustad.com  you are actually going to a host which has an IP address, but you do not have to remember the IP Address of every WebSite.

This is because Domain Name Service (DNS) helps map a name such as https://networkustad.com to the IP address of the host where the site resides. This clearly makes it easier to find resources on a network. When you type in the address of a website in your browser, the system first sends out a DNS query to its DNS server to resolve the name to an IP address. Once the name resolved, an HTTP session is established with the IP Address.

DHCP

Every host requires a logical address such as an IP address to communicate in a network. The host gets this logical address either by manual configuration or by a protocol such as DHCP. DHCP stands for Dynamic Host Configuration Protocol. It provide quick automatic, and central management for the distribution of IP addresses within a network.

To understand the importance of DHCP, imagine having to manage 10000 hosts in a network and assigning them IP address manually! Apart from the IP address, a host needs other information such as the address of the DNS server it needs to contact to resolve names, gateways, subnet masks, etc. We can use DHCP to provide all these information along with the IP address.

TCP

TCP stands for Transmission Control Protocol. It is the heart of the TCP/IP networks. The IP protocol deals only with packets, where the TCP enables two hosts to establish a connection and exchange streams of bits. TCP guarantees delivery of data between hosts and also guarantees; the packets delivery order.

IP

IP stands for internet protocol. It is the primary protocol in the Internet Layer of the Internet Protocol Suite. IP provides standard rules for sending and receiving data over the Internet. It allows devices running on different platforms to communicate with each other as long as they connected to the Internet.

UDP

UDP is Stands for “User Datagram Protocol”. The part of the TCP/IP suite of protocols used for data transferring. It is a “stateless” protocol because it not providing any acknowledgment of the packet receiving at the receiving ends. UDP protocol generally used for streaming media because of the low overheads.

It is simpler than TCP and lacks the flow-control and error-recovery functions of TCP. Thus, it uses fewer system resources. Difference between UDP and TCP is that UDP is sending data without ack but TCP is ever required ack.

ICMP

ICMP is Stands for “Internet Control Message Protocol. It defines a small number of messages used for diagnostic and management purposes. Ping and traceroute also use ICMP. When information is transferred over the Internet; computer systems send and receive data using the TCP/IP protocol. If there is a problem with the connection; error and status messages regarding the connection are sent using ICMP, which is part of the Internet protocol.