[bittorrent] Choice of listener ports

larytet.8708132 at bloglines.com larytet.8708132 at bloglines.com
Sat Mar 26 19:30:20 EST 2005

--- Kenneth Porter <shiva at sewingwitch.com wrote:
I was reading an article
on SlashDot in which a student was deprived of 
> Internet privileges for
operating a BT client:
> <http://ask.slashdot.org/article.pl?sid=05/03/25/1916233>

> Traditionally BT peers listen on ports 6881-6889, and trackers on 6969.
> those values aren't defined in the protocol; they're just conventions.
> occurred to me that one way to deal with blocking is to listen on a
> normally used for an "approved" service, such as 25, 80, 110 or 443.
> using mod_bt to run a tracker inside Apache can run the tracker
on the same 
> port as their regular web server. Others could use Apache
to proxy port 80 
> requests to their separate tracker program.)
> What
problems would you foresee from doing this?

intelligent statefull firewall
is not going to use port number as only indication of using P2P network. read,
for example P-Cube, Allot Communication, Expand Networks, Lancope Inc., Ellacoya
Networks, Packeteer web sites

Some P2P clients use random port numbers
- it does not help.

The only way i see is faked RTP/DNS/... packets with
encrypted payloads

see Data encryption and how to fight P-Cube, Allot Communication

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