SSH Components

SSH has mainly four components, SSH Transport Layer Protocol (SSH-TRANS), SSH Authentication Protocol (SSH-AUTH), SSH Connection Protocol (SSH-CONN) and SSH Applications, as shown in below image. These SSH components are supposed to run at the Application layer of TCP/IP protocol suite.

SSH Transport Protocol (SSH-TRANS)

SSH Transport Protocol (SSH-TRANS) is the component of SSH which allows to establish a secure connection between SSH client and SSH server over TCP. SSH Transport Protocol (SSH-TRANS) negotiates different security parameters between the client and the server, for example, encryption algorithm, HMAC algorithm etc, to create the secure tunnel between SSH client and SSH server.

SSH Connection Protocol (SSH-CONN)

SSH Connection Protocol (SSH-CONN) is the component of SSH, which allows to run multiple channels over the secure connection established.

SSH Authentication Protocol (SSH-AUTH)

SSH Authentication Protocol (SSH-AUTH) is the component of SSH which allows to authenticate the SSH client for the server.

SSH Applications

Once the secure connection is established between SSH client and SSH Server, SSH allows different application programs to use the established secure connection. Remote console login, SFTP (Secure File Transfer Protocol) etc., are the examples of different applications.