1.6. Connecting to a remote server through an SSH jump host

Procedure

1. If you connect through a jump server or more intermediary servers once, use the ssh -J command and specify the jump servers directly, for example:

   $ ssh -J <jump-1.example.com>,<jump-2.example.com>,<jump-3.example.com> <target-server-1.example.com>

   Change the hostname-only notation in the previous command if the user names or SSH ports on the jump servers differ from the names and ports on the remote server, for example:

   $ ssh -J <example.user.1>@<jump-1.example.com>:<75>,<example.user.2>@<jump-2.example.com>:<75>,<example.user.3>@<jump-3.example.com>:<75> <example.user.f>@<target-server-1.example.com>:<220>

2. If you connect to a remote server through jump servers regularly, store the jump-server configuration in your SSH configuration file:

   1. Define the jump host by editing the ~/.ssh/config file on your local system, for example:

      Host <jump-server-1>
        HostName <jump-1.example.com>

      • The Host parameter defines a name or alias for the host you can use in ssh commands. The value can match the real hostname, but can also be any string.
      • The HostName parameter sets the actual hostname or IP address of the jump host.

   2. Add the remote server jump configuration with the ProxyJump directive to ~/.ssh/config file on your local system, for example:

      Host <remote-server-1>
        HostName <target-server-1.example.com>
        ProxyJump <jump-server-1>

   3. Use your local system to connect to the remote server through the jump server:

      $ ssh <remote-server-1>

      This command is equivalent to the ssh -J jump-server1 remote-server command if you omit the previous configuration steps.