Linux Administration Cookbook

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If you're interested in seeing both servers running, there's a few methods of doing so.

On centos2, start with ss:

[vagrant@centos2 ~]$ sudo ss -tna -4State       Recv-Q Send-Q     Local Address:Port                    Peer Address:Port              LISTEN      0      128                    *:2020                               *:*                  LISTEN      0      128                    *:111                                *:*                  LISTEN      0      128                    *:22                                 *:*                  LISTEN      0      100            127.0.0.1:25                                 *:*                  ESTAB       0      0              10.0.2.15:22                          10.0.2.2:59594 

We can also use systemd's built-in commands:

[vagrant@centos2 ~]$ PAGER= systemctl | grep sshd  sshd.service                                                                             loaded active running   OpenSSH server daemon  sshd_2020.service                                                                        loaded active running   OpenSSH server daemon on port 2020

And lastly, we can use good old ps:

[vagrant@centos2 ~]$ ps aux | grep sshdroot 856 0.0 0.8 112796 4288 ? Ss 16:52 0:00 /usr/sbin/sshd -D -u0 -f /etc/ssh/sshd_config_2020 ...