SSH is slow to make a connection

I just installed RHEL 6.2, and whenever I try to SSH into my servers it's very slow. Before it displays the password prompt, it can take between 40 seconds and 60 seconds.

I found the solution of it.
This is slow because the OpenSSH daemon uses DNS to run a reverse lookup on the client hostname to make sure it's valid.

sudo vi /etc/ssh/ssh_config

Comment out the following lines 

#GSSAPIAuthentication yes
#GSSAPIDelegateCredentials no

OR

add this:

UseDNS no

Restart sshd deamon