Linux Tip - Disable Reverse DNS for SSHD

A very typical fix to disable DNS reverse lookups by the SSH daemon. Several reasons to disable it including:

  • non-Production test/dev/lab environments where there may be no reverse DNS
  • external facing servers who may get scripted SSH brute force attacks
  • laggy DNS and you really want to get in fast

Just add the like "UseDNS no" to your /etc/ssh/sshd_config file and restart SSHD.