Just quick notes, before I froget.

Docs

z/OS OpenSSH User’s Guide

Log in

Client issues

Tell me why things went wrong.

ssh -v user@host

Force password authentication - for example if you have many ssh keys and they get all rejected by server and the server then closes the connection because of Too many authentication failures.

ssh -o PreferredAuthentications=password user@host

SSH server logging

Add these lines to /etc/ssh/sshd_config

SyslogFacility DAEMON 
LogLevel DEBUG3       

• SyslogFacility DAEMON will print logs to MVS console log
• LogLevel DEBUG3 will print a lot of detailed messages

Start the SSH daemon

From operator console

S SSHD

From shell

_BPX_JOBNAME=SSHD /usr/sbin/sshd &. # stdin and stdout are /dev/null, stderr is /etc/log

To override the stderr

_BPX_JOBNAME=SSHD /usr/sbin/sshd 2>/tmp/sshd.stderr &

Stop the SSH daemon

D A,SSHD*              returns an ASID
D OMVS,ASID=aaaa.      returns PID
F BPXOINIT,TERM=ppppp. shut it down

kill $(cat /var/run/sshd.pid)  # PidFile option configured in /etc/ssh/sshd_conf

Restart the SSH daemon

This is useful to quickly reload configuration without terminating existing SSH connections

kill -s HUP $(cat /var/run/sshd.pid)