SSHd is by default configured to perform reverse
DNS Lookup everytime you connect to the server. This is especially true for
Red Hat and could significantly increase login time.
UseDNS Specifies whether sshd(8) should look up the remote host name and check that the resolved host name for the remote IP address maps back to the very same IP address. The default is “yes”.
To fix this you'll have to disable the
UseDNS option on the server via the following steps;
SSHd config file.
UseDNSand set the value to