11 Protocols You’ve Got To Know

OK, so let’s start by asking: What exactly are Protocols?

Protocols are rules.

Think of protocols as ‘accepted standards’ – which we all agree to.

A good example are the days of the week.

It is with almost absolute certainty that every one of 196 countries in the world agrees that there are seven days in the week and that there are 24 hours in a day. If every country had a different way of calibrating an earth day from dawn to dusk it would be very difficult to communicate with each other, hence the need to have protocols.

Many of our students are either studying infosec certs like Security+, OSCP, and Certified Ethical Hacker. A lot of the content and syllabus will refer back to protocols so you really have to know these!

Before we begin, we have to mention that are literally dozens more of these – the list below is in our opinion the most important protocols. If you think we are missing important ones please add a comment below.

IP: Internet Protocol

The Internet Protocol is where it all begins. IP is responsible for basic networking. The core of the IP protocol works with Internet addresses and every computer on a TCP/ IP network must have a numeric address.

FTP: File Transfer Protocol

Where would be without FTP? The oldest (its 42 years old this year!) and frankly the best known of all protocols outside of IP. The original specification for FTP was compiled by Abhay Bhushan and published on April 16th, 1971. There have been many updates including the very latest which allows the protocol to support IPv6 (more on that later).

FTP can be defined as a standard network protocol that is especially used to transfer files from one host (machine/ operating system) to another host over a TCP/ IP based network.

Typically FTP is used to push files up or down to a server. Since Concise Courses is an information security training school, we have to jump up and down at this point and say that FTP is hugely insecure when left at its’ default settings. The reason for this, and why many advise against using FTP is because users can, and do, authenticate themselves using only clear-text which can easily be read by a Man In The Middle attack or otherwise.

To secure FTP the user can connect anonymously but only if the receiving server is configured to allow it. A better and more robust solution is to use FTPS or better still, the SSH File Transfer Protocol.

SSH: Secure Shell

SSH and FTP are often mentioned in the same breath. Invented in 1995 Secure Shell’s definition is “a cryptographic network protocol for secure data communication”. SSH allows for remote command-line login and remote execution. It has many of the functions of FTP but is more secure. The latest versions are referred to as SSH-1 and SSH-2.

SSL: Secure Sockets Layer

SSL allows security by allowing applications to encrypt data that go from a client to a matching server (for example).

TELNET (telnet)

The telnet (written in small caps) lets you connect to a remote computer and work as if you were sitting in front of your computer, no matter how far away you are. This is another old technology, first invented in 1969. By default, telnet does not encrypt data sent over the network so use with caution!

SMTP: Simple Mail Transfer Protocol

The Simple Mail Transfer Protocol is the protocol for Internet email. It transfers email amongst computers. The majority of computers in the wild understand SMTP, but some do not.

POP3: Post Office Protocol

The Post Office Protocol (latest version is ‘3’) provides basic client/ server features that help the user download email from a POP3 email server to a computer (be it mobile or a desktop). The main purpose of the protocol is to allow users to access their email more freely.

IMAP4 Internet Message Access Protocol

The Internet Message Access Protocol and POP3 are sort of connected. Abbreviated to IMAP, this protocol provides a richer set of features when compared to POP3. Worth mentioning that although IMAP and POP3 both help to manage email, they cannot function together, i.e. the user must choose one or the other.

HTTP: HyperText Transfer Protocol

OK, if you don’t know this one then we really recommend you start your training from the basics! HTTP is the key protocol for being able to transfer data across the Internet. HTTP allows the transfer of HyperText Markup Language (HTML) and other related scripting languages (like CSS) to travel from servers to browsers.

HTTPS: Hypertext Transfer Protocol Secure

Think of HTTPS and a secure version of HTTP. The Hypertext Transfer Protocol Secure (HTTPS) protocol facilitates secure communication over a network. Strictly speaking, HTTPS is a layer on top of HTTP using SSL (see above).

SIP: Session Initiation Protocol

We wanted to include SIP as our tenth protocol owing to an excellent Hacker Hotshot session we had recently titled: “Learn How To Crack SIP Authentication & Listen To VoIP Calls In 15-Minutes!”.

SIP is vital to understand if you are interested in a career in information security, and our video will certainly help your learning. In summary, SIP is a signaling communications protocol, which is commonly used for managing multimedia communications such as voice and video calls over Internet Protocol (IP) networks – i.e. VoIP. SIP is relatively secure but as we demonstrate in our video, it can be compromised using Wireshark and a few other tools.

In Summary

That’s it!

Yes, we know, there are many many other protocols that we can add – and if you think we should include another for this post, then please drop a comment below, we’d love to get your feedback!