OpenSSH FAQ
Introduction
OpenSSH is not always simple, which is why a small documentation is useful.
FAQ
fatal: Timeout before authentication for @ip
Your DNS on your SSH server might not be up to date. Check them.
Some clients take a long time to connect
On the SSH server, it is very likely that the server is trying to resolve names, which is not always possible or practical. The solution is to disable this (/etc/ssh/sshd_config):
You just need to restart the SSH server.
Unspecified GSS failure. Minor code may provide more information
Add this line to your configuration (/etc/ssh/sshd_config):