[Solved] How To Fix Slow/Delayed SSH Login Issue in CentOS/RHEL

ISSUE/ERROR:

• Long Delays when login into CentOS/Linux servers via SSH
• SSH Login prompt takes lots of time to appear
• Very Slow SSH logins when using SSH to remote connect

Recently we faced strange issue when trying to SSH into one of our new remote servers. When we SSH (using PUTTY) to the server it took more than a minute to the login prompt to be visible. First we though, it might be random network issue. But we were wrong. It stats to happen each and every SSH login. 

HOW TO FIX:

Fix for this can be different based on the OS you are using but for CentOS and Linux versions, the Fix is more or less similar.

#1. Go to /etc/ssh/sshd_config (or /etc/sshd_config)

#2. Change "UseDNS" to "no" 

#3. Change "GSSAPIAuthentication" to "no"

#4. Restart the server using "service sshd restart"