some civically irresponsible exits?

Jacob Appelbaum jacob at appelbaum.net
Wed Oct 31 23:08:55 UTC 2007


Scott Bennett wrote:
>      The documentation that comes with tor rather strongly suggests that exit
> servers should have exit policies rejecting the SMTP port (25).  The tor
> sample torrc includes this rejection as well.  This rejection of exits to
> port 25 would seem to be a Very Good Thing (tm) in light of the rapidly
> growing waste of Internet bandwidth in the form of massmail.
>      Nevertheless, I decided a few minutes ago to take a peek at reality by
> playing with the "exitlist" python script in tor-0.2.0.9-alpha/contrib.  Using
> one of the IP addresses for the system on which I get most of my email, I get:
> 

I don't see this as a problem at all. I see it as totally responsible.

Some exit node operators allow outgoing port 25. They probably also
allow port 6667, port 80, port 443, etc. Any and all of these ports can
be abused.

Mail admins that want to block Tor from sending possible email to their
servers can easily use the TorDNSEL:
http://exitlist.torproject.org/

I run that server and if you're in need of help using its features, feel
free to write me. Tup wrote the Haskel that's powering it and it's been
running fine for months.

A mail admin should assign a score based on the results of an exitlist
rbl test. Hopefully they won't just throw it away. I hear people use it
for the same reasons that people use any other exit port.

-Jacob



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