Unknown Host

Posted on April 25, 2019 by Destry Hines

This morning we had an DNS outage on one of our servers. Local cron jobs that were trying to connect to local domains were failing with:

Looking up www.example.com
Unable to locate remote host www.example.com.
Alert!: Unable to connect to remote host.
lynx: Can't access startfile http://www.example.com/process.php

After restarting a few services and even restarting the server, nothing worked. After some additional reseach, and a bit of head scratching, I decided to flush the DNS cache to see it that would clear up the problem.

The following command will flush the cache on a Centos server:

service nscd restart

After that, everything was once again running smoothly.