[ubuntu-uk] Broken Synaptic

Andrew Oakley andrew at aoakley.com
Wed Feb 20 09:17:11 GMT 2008

taufanlubis wrote:
> If you use proxy or firewall, don't forget to open port 53.
> It's used by Ubuntu to get update from Repository Server

Um... port 53 is DNS. It is used by everything from Ping through 
Firefox. It is the system that translates doman names such as 
"www.bbc.co.uk" to numbers such as "" - in the same way that 
you can't dial the name "Dominos Pizza" from your telephone; you have to 
look up their telephone number.

Without DNS your system is basically not going to be able to use the 
internet in any common way.

Your comment is correct - port 53 IS required by Synaptic - but it is 
also required by almost every other internet-aware program in the world. 
If port 53 was blocked, you would probably be aware of a lot of other 
problems long before you realised Synaptic was broken.

For example, if port 53 was blocked, you wouldn't be able to receive 
email and you wouldn't be able to read the ubuntu-uk list. Therefore I 
think we can rule this out as the problem.

Andrew Oakley

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