I rebooted my server, and for some reason sshd doesn't
start up automatically. I forgot this, and when I ran MacSSH
on my client machine, it kicked me out with a Type 2 error
and no further explanation. I realized then that I needed to
start sshd, which I did with plain telnet, but it seems like you
should report back that a server isn't running sshd or
accepting port 23 connections or something similar.