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
This course is made for Linux admins who seek to secure their Linux work environment by mastering Linux SSH security!
Written by Mohd Shakir Zakaria.
Last updated on 2019-02-12.