SSH session slow to start? It's the DNS mate!

Ever tried logging into a machine with ssh and found you have to wait much longer than reasonable for the session to start?

There are a couple of very simple ways to fix that:

add "UseDNS no" to /etc/ssh/sshd_config

or

add the client's net address to the server's /etc/hosts

and/or its systemd-logind

remedy:

systemctl restart systemd-logind