The configuration file

It is possible to specify host configuration in .ssh/config. This can be helpful in various situations, as it allows you to specify:

• Custom (friendly) names for hosts
• The default user to use
• The port
• Tunnels to open before connecting
• Identity files (keys)

Among many other things.

Note

If a server you connect to has a permanent IP address, it can make sense to specify it in your SSH config file to avoid relying on DNS or CDNs during a disaster recovery situation.

SSH configuration files aren’t particularly complicated, so we’ll show you an example here that uses many of the available features:

# Set Defaults for all hosts using the glob character (*)Host *
  ServerAliveInterval 30     # Check if the connection is alive every 30 seconds
  ForwardAgent yes           # Forward SSH agent to the remote host
  Compression yes            # Enable compression
  IdentityFile ~/.ssh...