SSH server is by default configured to perform reverse
DNS lookup of your
IP address every time you try to log in to the server. It could slightly improve logging and security, but would significantly increase login time.
Basically the login prompt could take a while to appear as the server will perform reverse
DNS lookup on the incoming
IP address prior to presenting the login prompt.
You can fix this issue by disabling the
UseDNS directive on the
SSH server from the terminal.
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”.
SSHdconfiguration file using a text editor.
$ sudo vi /etc/ssh/sshd_config [sudo] password for user:
UseDNSdirective and set the value to
Add the line if it doesn't already exist and remove the
# at the beginning of the line if existing line starts with
$ sudo systemctl restart sshd
|Red Hat Enterprise Linux|
|SUSE Linux Enterprise Server|
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