This is an old revision of the document!

SSH

Set Up SSH Keys

ssh -v ...

Take care of both with this one-liner:

On the Client PC:

echo "Host *
        ServerAliveInterval 60
        GSSAPIAuthentication=no" >> $HOME/.ssh/config

(be sure to copy and paste everything including the CRLF's and spaces)

If a permissions error is thrown:

chmod 600 /home/gcooper/.ssh/config

Adjust your firewall first or you may lose access!

vim /etc/ssh/sshd_config

Port 2222

service sshd restart

This technique is used to access an SSH host behind a NAT firewall.

On the middle-man host with a real static IP address:

Set “GatewayPorts yes” in /etc/ssh/sshd_config
- Restart sshd if sshd_config changed
Configure to use SSH keys rather than passwords
- Less trouble
- More secure

On remote host (behind NAT) that you want to access:

ssh -R 22222:localhost:22 root@middleman

or if SSH is listening on a non-standard port:

ssh -R 22222:localhost:22 root@middleman -p 2222

From your workstation, connect through the middle-man PC:

ssh -p 22222 root@middleman

Use AutoSSH to keep a tunnel up constantly.