The OpenSSH configuration file, ssh_config, is used to set options for the ssh client. The ssh_config file is located in the /etc/ssh directory on most systems.
Here are some examples of common options that can be set in the ssh_config file:
Host: This option specifies a hostname or a pattern to match multiple hostnames. For example, you can use the Host option to specify a hostname or an IP address for a remote server that you want to connect to:Host example.com Host 192.168.1.100
You can also use wildcards to match multiple hostnames:
Host *.example.com
Port: This option specifies the port number to use for the connection. By default, ssh uses port 22 for the connection. You can use the Port option to specify a different port number:Port 2222
User: This option specifies the username to use for the connection. You can use the User option to specify a different username than the one you are currently logged in as:User myuser
IdentityFile: This option specifies the path to a private key file to use for authentication. You can use the IdentityFile option to specify the path to a private key file that you want to use for the connection:IdentityFile ~/.ssh/id_rsa
ForwardAgent: This option specifies whether to forward the ssh-agent connection to the remote server. You can use the ForwardAgent option to enable or disable agent forwarding:ForwardAgent yes
ForwardX11: This option specifies whether to forward X11 connections to the remote server. You can use the ForwardX11 option to enable or disable X11 forwarding:ForwardX11 yes
Compression: This option specifies whether to enable compression for the connection. You can use the Compression option to enable or disable compression:Compression yes
ServerAliveInterval: This option specifies the interval in seconds to send a null packet to keep the connection alive. You can use the ServerAliveInterval option to specify the interval in seconds: