blocking peer-to-peer filesharing programs

Scott Francis darkuncle at
Mon Dec 10 20:54:40 UTC 2001

On Mon, Dec 10, 2001 at 11:48:33AM -0800, dani-post at said:
> I realize this may be a touchy subject.  For legal purposes I'll state that
> I'm making these inquiries as an academic excercize, as well as to enable me
> to block peer-to-peer programs on my own personal home network. The last thing
> I'd want to do is rob anyone of their free speech or "rights" to distribute
> illegal copies of copyrighted material.

Stating that something is a touchy subject, and proceeding to troll is not
very productive (unless of course you are merely trolling ...) If you are
seeking serious technical advice, prefacing your messages with political
rhetoric is likely going to hamper your efforts.

(and on an unrelated note, 80-column format lines are a nice touch for those
of us reading mail on a CLI mail reader ... pretty much every major mail
client has an option to wrap lines at X columns these days.)

> Anyway... I'm interested in developing and studying comprehensive firewall and
> content-filtering techniques for disabling peer-to-peer filesharing
> applications (e.g. those using gnutella, fasttrack, other napster-style
> directory and download engines or stacks).  If anyone knows of a mailing list
> /user group that has similar interests, or if you have similar interests,
> please email me off-list.

If you really want to stop P2P filesharing apps, you had better be prepared
to constantly audit network traffic, and have an ever-expanding list of
blocked ports. Don't forget about the 'old skool' filesharing systems like
NFS, windows shared directories, IRC, FTP/HTTP download sites, etc. From a
technical perspective, I'm not sure there is any single network-level
characteristic that is shared by all P2P systems, and not shared by any other
systems. Communication types vary, ports vary, protocols vary ... there may very
well not be any single feature to look for in network traffic that will block
all P2P traffic at this point in time.

Your best bet may just be to resign yourself to regular research, and make
sure that the ports you're blocking aren't also utilized by 'legitimate'

I'm sure, given the variety of networks represented by this audience, there
will be someone with some solid experience in this area, as opposed to my
(admittedly) academic conjecture. Maybe I helped get the ball rolling,

> Thanks all.
> - Dani

Scott Francis                   [email protected] [home:] d a r k u n c l e . n e t
UNIX | IP networks | security | sysadmin | caffeine | BOFH | general geekery
GPG public key 0xCB33CCA7              illum oportet crescere me autem minui
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 872 bytes
Desc: not available
URL: <>

More information about the NANOG mailing list