How to configure DNS client
This article explains how to configure a UNIX system (HP-UX, LINUX) domain name client service.
Configure DNS time outs
To setup the time frame that the server is going to wait before it attempt to query the alternative DNS servers in the DNS server list on /etc/resolv.conf. The resolv.conf file manpage (# man 4 resolv.conf) turns to be ambiguous but the procedure is very simple.
An usual case for this situation is an enviroment where the web application server has 2 or more DNS servers that can be query. If the primary DNS server doesn't respond, the server will be waiting for a long time until it attempt to query the second server. In real life this means you can lose a client because the web form is not responding fast enough.
The way to reduce the time is adjust the /etc/resolv.conf file.
-> /etc/resolv.conf domain abz.xyz.com nameserver 192.168.0.1 nameserver 192.168.0.2
You only need to add two more entries at the end of the file.
-> /etc/resolv.conf domain abz.xyz.com nameserver 192.168.0.1 nameserver 192.168.0.2 retrans 5000 retry 1
It means that the server is going to wait 5 seconds (retrans) before it attempt to query the second DNS server, and it's going to query the current DNS server only one time (retry).
You may want to verify the new configuration by issuing the nslookup command
# nslookup www.hp.com
- HP-UX Reference - resolv.conf(4)
- Unknown Author
- Alejandro Marin Badilla - Editor