How to change the default DNS Servers in a Thomson Router

‎31-07-2009

First a little background. Unlike many routers many Thomson models have emasculated firmware which allows only very limited controls from the web interface and many commands are only available using Command Line Instructions (CLI). In order to change the DNS servers it is necessary to utilise this feature via the telnet command.

These instructions are known to work on the Speedtouch ST546 and ST585 v6, the Gateway TG585 v7 and v8 and the TG582n using the appropriate usernames and passwords.

Operating systems known to be supported in this guide are Windows XP, Vista and Windows 7

For Vista and Windows 7 it will be necessary to enable the telnet command as it is disabled by default.

To do this go to “Control Panel”, “Programs and Features” then “Turn Windows Features on or off”. You should then scroll down and tick “Telnet Client”

It will now be necessary to open a DOS window.

In XP and Vista it is relatively easy. Click on the start menu button and select “Run” then type CMD and then press the Enter key. This will open a DOS window.

In Windows 7 it is more difficult as the Run command is hidden by default. The easy way out of this is to right click on the desktop, select “New” then “Shortcut” and type or paste this in the location box “C:\Windows\System32\cmd.exe” without the quotation marks assuming that Windows is installed in the C: Drive. This shortcut will then open a DOS window.

Commands we will be using in this guide

Note that text enclosed in <> is explanatory and is not to be typed. Also replace 4.2.2.1 with your selected DNS server.

dns server route list <lists all the current DNS servers>

dns server route add dns=4.2.2.1 metric=1 intf=Internet <adds a new DNS server in accordance with the server numbers you want. The metric value defines the priority. As the default priority is 10, use a number smaller than that to avoid your setting being overwritten by the automatically generated Plusnet ones.>

dns server route delete dns=4.2.2.1 <removes a DNS server from the list>

saveall <this command saves all the changes to non volatile memory otherwise on a reboot of the router all the changes will be lost>.

Some of the DNS servers which can be used are as follows

OpenDNS

208.67.220.220
208.67.222.222

Plusnet

212.159.13.49
212.159.13.50
212.159.6.9	<in my experience usually the primary DNS automatically allocated>
212.159.6.10	<in my experience usually the secondary DNS automatically allocated>

For guidance I would suggest using a Plusnet one first and an OpenDNS one second as this covers for the case where one or the other is having trouble. In this situation the metric would be 1 for the Plusnet one and 2 for the OpenDNS one thereby setting the priority as you want it. You could, of course, use any numbers you wish and as long as they are less than 10 they will have a higher priority than the automatic ones.

Step by Step Guide

Open DOS window

Type telnet 192.168.1.254

Username Administrator

Password blank (unless you have changed it)

Note: the Username and Password to use depends on the router you are using. Please see the guide that came with your router for the appropriate ones to use.

You should then see something like this

Username : Administrator
Password :
------------------------------------------------------------------------
______                   SpeedTouch 585
___/_____/\
/         /\               6.1.4.3
_____/__       /  \
_/       /\_____/___ \   Copyright (c) 1999-2006, THOMSON
//       /  \       /\ \
_______//_______/    \     / _\/______
/      / \       \    /    / /        /\
__/      /   \       \  /    / /        / _\__
/ /      /     \_______\/    / /        / /   /\
/_/______/___________________/ /________/ /___/  \
\ \      \    ___________    \ \        \ \   \  /
\_\      \  /          /\    \ \        \ \___\/
\      \/          /  \    \ \        \  /
\_____/          /    \    \ \________\/
/__________/      \    \  /
\   _____  \      /_____\/
\ /    /\  \    /___\/
/____/  \  \  /
\    \  /___\/
\____\/
------------------------------------------------------------------------

I will now use the commands to show the effects – note that these were done with the router off line so it doesn’t show the default Plusnet servers.

{Administrator}=>dns server route list
DNS Server       Source              Domain            Metric  Intf     State
208.67.220.220                                         1     Internet
{Administrator}=>dns server route add dns=212.159.13.50 metric=2 intf=Internet
{Administrator}=>dns server route list
DNS Server       Source              Domain            Metric  Intf     State
208.67.220.220                                         1     Internet
212.159.13.50                                          2     Internet
{Administrator}=>dns server route delete dns=212.159.13.50
{Administrator}=>dns server route list
DNS Server       Source              Domain            Metric  Intf     State
208.67.220.220                                         1     Internet
{Administrator}=>saveall
{Administrator}=>