Some servers are meant to only serve few specific ports and in this case, server administrator should disable the normal login process. In my case, I wanted to have alerts when someone tries to even login to this server and I configured /etc/hosts.deny file to send alerts to me. This is good for at least Solaris OS.
# cat /etc/hosts.deny
ALL: ALL: /usr/ucb/finger -l @%h 2>&1 | /bin/mailx -s
"Someone is knocking at `hostname`" unixgeek@somecompany.co
