SSH Protocol's features can be changed using the sshd_config file.The sshd_config file is the main configuration file that allows the user to make the changes in the features of SSH protocol. This file resides in /etc/ssh folder. There are many features for this protocol and these can be made or changed according to the users needs. By making configuration changes, the protocol also provides more security to the user and server/system that we are using. Some of the main features of the SSH protocol are listed below.
The port option specifies which port the SSH daemon listens for incoming connections. The default port specified for this is port 22.
This address specifies the IP address of the interface network on which ssh server daemon socket is bind. The default ListenAddress is 0.0.0.0.
This option is useful when we create the server key. For example: To enable key authentication we usually create the public/private key pair and this option is used when creating this key. From this feature the key is generated with the bits mentioned in this option.
LoginGrace time 600
The 'LoginGrace time' option specifies how long the server has to wait untill getting disconnected from the server if the user has not successfully disconnected from the server.
The 'KeyRegenerationInterval' option specifies how long the server should wait before it automatically generated the key. The 'KeyRegenerationInterval' is shown in seconds.
This option permits root login via SSH to server. This option should always be set to 'Yes' so as to allow SSH access for the root user to server.