debug1: An invalid name was supplied Cannot determine realm for numeric host address

If you have a slow SSH connection to a server with the following message :

debug1: An invalid name was supplied
Cannot determine realm for numeric host address

Make sure that the server you try to reach has a well-configured reverse DNS. Then, you can desactivate GSSAPI authentication by adding the following line to your ssh client configuration file :

fool@localhost:~$echo “GSSAPIAuthentication no” >> $HOME/.ssh/config

You should be able to connect to your server through SSH quicker.