Secure Socket Shell or Secure Shell is a network protocol that provides users with a secure path to securely access computers across the network. This term refers to a set of tools that also implement the SSH protocol.

What is the SSH protocol?


This protocol provides an encrypted connection between two computers connected over an open network such as the Internet. System and network administrators widely use SSH to manage systems and applications remotely, allowing them to log in to different computers across the network, execute commands, and retrieve files from a single Transfer from one computer to another.

Applications using SSH

The uses of SSH, which is pronounced as SSH, are briefly as follows: It
is used to provide secure access to users.
Easy and automatic transfer of files between devices. Manage
remote command issuance and execution of network infrastructure and other critical system components.

Some features of SSH

This protocol has many uses and the good and unique advantages of this protocol are what made SSH so popular and widely used, we will discuss some of these advantages and features below:

Remote Secure Login

Assuming that you have entered several user accounts from different devices. Protocols such as TELNET allow you to log into a computer from another computer. The biggest problem is that these protocols transmit usernames and passwords in plain text across the Internet and can be intercepted by any third party. Therefore, SSH was created to prevent such problems by sending this information in an encrypted form that cannot be hacked and accessed by an external party, and the entire session is also encrypted in the same way.

Secure file transfer

If you have several different accounts on multiple computers and want to transfer a file from one to another, traditional transfer programs or traditional protocols do not provide secure transfer of these files by transferring them over the network but using SSH. Files can be securely transferred between devices.

Remote command execution

Suppose a system administrator needs to run a command on several machines. The Secure Transport Protocol, or SCP, provides the ability to do this by encrypting each command as it passes between devices.

keys (SSH keys)

When using a group of accounts, you need to come up with a set of passwords for all of them, and it takes a lot to remember. Not only that but remembering the password associated with each account is the biggest problem. And the mechanism of writing it down in a special notebook sometimes does not help, especially if you forget to keep this piece of paper every time. In order to find a solution to this problem, the idea of ​​Secure Transfer Protocol keys emerged as an alternative to passwords. These keys form a set of encrypted bits that can only be used to identify the user after entering the appropriate password. This way all accounts can be securely authenticated without having to remember passwords.

Access control

Sometimes one of us has to allow a friend or other person to use our PC for certain purposes, and that person can use the account without knowing our password, in addition to our ability to limit access authority. Have a user

The working mechanism of the SSH protocol

Network communication using a secure transport protocol requires three layers to function seamlessly as follows:

  • Transport Layer: This layer performs the exchange of cryptographic keys between devices and manages communication during the session.
  • Authentication layer: This allows a user to access another computer using different authentication methods. The most common method is to use a password and username.
  • Communication Layer: It is the layer on which the SSH interface runs and contains the access programs.

The main differences between SSH and TELNET

Both protocols theoretically provide the same service, which is connecting to a remote computer. However, TELNET is a traditional protocol, while SSH offers advanced features:

  • TELNET offers no security aspect, while SSH is more secure.
  • Data is transmitted in plain text, which makes it vulnerable to hacking, while SSH uses encryption in data transmission.
  • TELNET works with private networks but SSH works with public networks.
  • TELNET connects over port 23 over TCP/IP and SSH over port 22.