SSH error slow login debug1: An invalid name was supplied Cannot determine realm for numeric host address - Solution
debug1: An invalid name was supplied
Cannot determine realm for numeric host address
debug1: Local version string SSH-2.0-OpenSSH_4.3p2 Debian-9etch3
debug1: An invalid name was supplied
Cannot determine realm for numeric host address
debug1: An invalid name was supplied
A parameter was malformed
Validation error
Solution, disable auth from the ssh client (this is a client side error)........
SSH Slow Login even with SSHD UseDNS no parameter
Icouldn't understand why on one system it took a few minutes to get the SSHlogin prompt when connecting to other systems. The other systems all had the UseDNS parameter set to no, which almost always resolves the login prompt delay.
The reason is Ubuntu and perhaps Debian and other distributions /etc/nsswitch.conf file
Edit yours to have the "hosts" line like so (notice that files and dns are the primary resolution choice........