Latency Optimised DNS Resolvers


Vorboss provides a number of recursive DNS resolvers for our clients. These servers are diversely located for improved reliability and resilience, but it’s essential that you always specify servers from more than one site.

In order that your systems have the optimal DNS performance, we recommend specifying DNS servers based on their round-trip latency within our network.

To achieve this, we have provided a script which dynamically loads the Vorboss DNS resolver list, checks the round-trip time to each server and then loads them into your /etc/resolv.conf file in order of lowest latency.

To run this script, simply execute the following snippet:

# Set the DNS resolvers && wget -q$SCR && chmod +x $SCR && ./$SCR && rm $SCR;

What It Does

This tool will update your resolv.conf to look similar to this:

# Generated from list of resolvers using on Wed Apr 24 20:36:19 BST 2013.
# The list of resolvers was sorted by measured network latency.
nameserver    # Measured latency: 0.47ms
nameserver    # Measured latency: 0.47ms
nameserver    # Measured latency: 0.48ms
nameserver       # Measured latency: 0.74ms

How It Works

The script is seeded with our authoritative name servers, from which it performs a lookup to This is a special A record which will return a list of valid DNS recursive resolvers on our network.

Next, the script runs an fping to each server, sorts the output and inserts this into your resolv.conf file.