” Our Honorable President will be the chief guest of Convocation Ceremony! The accomplishments will be awarded to the students following certain protocols. ” These are the words I heard when I have attended a convocation ceremony. The point to focus here is not our President, its Protocol. What is a protocol? Why it is necessary? What is it in our CS & EH? To the answers we go now…
Simply, a set of rules that are followed in executing a program is protocol. These protocols are not only for government officials or state affairs, these are applicable to networks as well to connect across globe. For a security specialist, it is necessary to have knowledge about networking inorder to safeguard network from attackers! Now, we shall learn about some of the network protocols that are commonly used.
Internet Protocol (IP):
We all might have heard about IP address mostly. An IP address is like an address on the post to which that particular post needed to be delivered. IP address is an address allocated to our hardware inorder to connect to the network or to deliver data packets to a targeted device. There are mainly two types of IP addresses used mostly. IPv4, a 32-bit number, that gives almost 2^32 possible addresses. As a growth in number of users, IPv6 was being introduced in 1998 that is 128-bit. It has almost 2^128 possible addresses, which are sufficient of foreseeable future.
Transmission Control Protocol (TCP)
TCP defines how a network conversation can be established to exchange data from both the ends. It takes messages from a server and converts them into packets, like a message written on a puzzle, and delivers to the target. Actually, TCP and IP works together to deliver packets and to define how networking works. Together they are referred as TCP/IP protocols. More learning!
Hypertext Transfer Protocol (HTTP)
HTTP, an application layer protocol, is basically a foundation protocol for communications for the World Wide Web (WWW). It follows a classical client-server model, in which a client (basically browsers) ask for a request and wait until the response from server. HTTP is a stateless protocol, as stateless firewalls, meaning servers do not keep a track of data between request and response. The default port of HTTP is 80 and 443 is the secure port.
File Transfer Protocol (FTP)
FTP is used for file transfers across the servers. To download a file or upload a file to the hosted website, we use FTP client. It is the oldest protocol but a convenient method of transferring files. These FTP connections can also have active and passive modes. Active modes are the most common, and allow open communication between the server and the device over both channels, with the server taking an active role in establishing the connection by approving requests for data. However, this mode can be disrupted by firewalls and similar issues, so there’s also a passive mode where the server pays attention but doesn’t actively maintain the connections, allowing the other device to do all the work. The default port for FTP is 20/21. Further…
Secure Shell (SSH)
It is a method of communicating with a computer network securely in an unsecured network. Many applications including, remote control access, login and modifying data on the host computer, etc. SSH is based on Unix shell and those commands can be executed to create, modify and transfer files from a remotely connected machine. The default port is 22. Learn More!
Teletype Network (Telnet)
Telnet is an application protocol to provide remote connection on TCP/IP networks. Unlike SSH, it doesn’t provide a secure network but gives a basic remote connection without any encryption. These provide a bidirectional interactive text oriented communication using a virtual terminal connection.
Dynamic Host Configuration Protocol (DHCP)
DHCP is a network protocol that assigns unique IP address to the devices connected to Internet. This resolves the issue of static allocation of IP address. It can stretch IP addresses by limiting how long a device can keep an individual IP address. Learn more!
Post Office Protocol (POP)
POP is a standard mail protocol used to retrieve mails from the server to the local computer. The users using POP for mail, can view their mails on the local computers but once they are downloaded from the server the mail contents are deleted from the remote server. So, POP is not suggested if you are accessing your mail from different locations. Since the mails are downloaded and deleted, they can be read even if offline and the space your mail using on the server will also be reduced. The default port is 110 (non encrypted) and 995 is the secured. Today, most commonly POP version 3 is being used.
Simple Mail Transfer Protocol (SMTP)
SMTP is an application protocol that is used to send mails across a Internet. The client who wants to send the mail opens a TCP connection to the SMTP server and then sends the mail across the connection. The SMTP server is always on listening mode. As soon as it listens for a TCP connection from any client, the SMTP process initiates a connection on that port. After successfully establishing the TCP connection the client process sends the mail instantly. The default port is 25. Further reading!
Domain Name System (DNS)
Basically, DNS is the phone book of Internet. We generally access websites using domain names, like google.com, instead of IP addresses. It converts domain names to IP addresses and send necessary response. The default port is 53. More learning!
Internet Message Access Protocol (IMAP)
IMAP is also a protocol used to retrieve mails from the server to the local computer. But unlike POP, it doesn’t delete the data from the mail server. The default port is 143 and 993 is the secured.
Simple Network Management Protocol (SNMP)
It is an application layer protocol used to organize, monitor, detect faults and sometimes to configure the networks. It is also used to alert Central Servers when an action is being done. The default port is 161. Read More!
Hypertext Transfer Protocol on SSL/TLS (HTTPS)
It is used along with HTTP in a secure environment provided by SSL (Secure Sockets Layer) and TLS (Transport Layer Security). The default port is 443.
There is much more in networking to work on. But the concepts that are required for CS & EH will be posted accordingly. Stay updated! Till then, Have a happy and healthy learning!
Stay Home Stay Safe!!!
Techprodezza 
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