Brand new ubuntu installation:

$ lsb_release -a

No LSB modules are available.

Distributor ID: Ubuntu

Description:    Ubuntu 20.04.1 LTS

Release:        20.04

Codename:       focal

ssh.service fails to startup due to port 22 already in use:

$ sudo service ssh status

● ssh.service - OpenBSD Secure Shell server

     Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)

     Active: failed (Result: exit-code) since Thu 2021-02-04 14:10:27 CST; 11min ago

       Docs: man:sshd(8)

             man:sshd_config(5)

    Process: 2041 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)

    Process: 2042 ExecStart=/usr/sbin/sshd -D $SSHD_OPTS (code=exited, status=255/EXCEPTION)

   Main PID: 2042 (code=exited, status=255/EXCEPTION)



Feb 04 14:10:27 ubu20a systemd[1]: Starting OpenBSD Secure Shell server...

Feb 04 14:10:27 ubu20a sshd[2042]: error: Bind to port 22 on 0.0.0.0 failed: Address already in use.

Feb 04 14:10:27 ubu20a sshd[2042]: error: Bind to port 22 on :: failed: Address already in use.

Feb 04 14:10:27 ubu20a sshd[2042]: fatal: Cannot bind any address.

Feb 04 14:10:27 ubu20a systemd[1]: ssh.service: Main process exited, code=exited, status=255/EXCEPTION

Feb 04 14:10:27 ubu20a systemd[1]: ssh.service: Failed with result 'exit-code'.

Feb 04 14:10:27 ubu20a systemd[1]: Failed to start OpenBSD Secure Shell server.

Only thing I see listening on port 22 is 1/init:

$ sudo netstat -tulpen

Active Internet connections (only servers)

Proto Recv-Q Send-Q Local Address           Foreign Address         State       User       Inode      PID/Program name    

tcp        0      0 127.0.0.53:53           0.0.0.0:*               LISTEN      101        34051      556/systemd-resolve 

tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN      0          37066      745/cupsd           

tcp6       0      0 :::22                   :::*                    LISTEN      0          34718      1/init              

udp        0      0 0.0.0.0:5353            0.0.0.0:*                           115        37068      743/avahi-daemon: r 

udp        0      0 0.0.0.0:52172           0.0.0.0:*                           115        37070      743/avahi-daemon: r 

udp        0      0 127.0.0.53:53           0.0.0.0:*                           101        34047      556/systemd-resolve 

udp        0      0 0.0.0.0:631             0.0.0.0:*                           0          39715      822/cups-browsed    

udp6       0      0 :::5353                 :::*                                115        37069      743/avahi-daemon: r 

udp6       0      0 :::39012                :::*                                115        37071      743/avahi-daemon: r 

While I can get ssh.service to startup on an alternate port (eg, port 2020) I'd like to understand, and fix (if possible), this current issue with port 22.

NOTES:

• linux sysadmin is not my strong point so if I'm missing something stupidly obvious ... go ahead and shoot the messenger


• if the answer is RTFM then a link to which FMTR would be appreciated


• I looked through the first dozen or so suggested 'duplicate' questions but didn't find anything applicable to this issue