Howto fix delay in SSH Login
DNS lookup query is an SSH feature that you can find in most Linux distros, this feature is responsible for the delay because SSH wait for a response of reverse DNS lookup query that is been made to DNS Server.
To overcome this issue, please follow these steps:
1- Edit /etc/ssh/sshd_config on sshd Server
and add this DNS option to the file:
save and exit
2- Now add the following line to your /etc/resolv.conf.