Re: [gentoo-user] Re: {OT} TCP or UDP?

[kashani <kashani-list@badapple.net>]

Etaoin Shrdlu wrote:
> On Tuesday 24 February 2009, 18:21, Florian Philipp wrote:
>> Nikos Chantziaras schrieb:
>>> Grant wrote:
>>>> How can I find out whether I should be specifying TCP, UDP, or both
>>>> for iptables (shorewall) config?
>>> By knowing the application's protocol for which you write the rules
>>> for :P [...]   So you have to research a bit to see if the
>>> application uses TCP or UDP.
>>   You can also have a look at /etc/services which lists the more
>> common protocols and their ports.
> 
> Or even sniff the traffic and see which protocols are used.
> 

	You're going to miss stuff that way. Take for example a DNS server. 
Normally requests are UDP over port 53. However once your request 
exceeds 512 bytes TCP is used on port 53. That rarely happens and in 
fact many ISPs don't seem to be aware that this can happen.
	Chances are you're going to find almost everything you need at 
http://www.shorewall.net/Documentation_Index.html which is going to far 
better than trying to cobble everything together yourself.

kashani