Improving DNS Lookups

This tip shows you how to improve DNS lookups by using multiple nameservers. This is useful if you've ever had your primary DNS server become unreachable for any reason.

Nameservers are listed in /etc/resolv.conf, one per line.

Code Listing 1: Example /etc/resolv.conf

nameserver 192.168.1.1 
nameserver 10.0.0.1

To improve DNS lookups, add multiple DNS servers (preferably on different subnets) and the following options to /etc/resolv.conf:

Code Listing 2: /etc/resolv.conf options

options rotate 
options timeout:1

This will use both nameserver in rotation and wait max. 1 second for answer before trying the next one.

From http://www.gentoo.org/news/en/gwn/20040202-newsletter.xml