pop3 and smtp over ssl [was: ssh]

[Roger Dingledine]

On Mon, Mar 05, 2007 at 01:40:19PM -0600, Mike Perry wrote:
> This is interesting.. According to running
> http://tor.eff.org/svn/trunk/contrib/exitlist, there should be about
> 20 nodes that exit to port 465.. The problem might be that these nodes
> are slower overall, and tend to drop more circuits.

They might be slow, and they might also be overloaded by folks who
want to use non-standard ports, so they get even more overloaded.

I know that there have been cases where nodes open up port 25 and then
become nearly useless because they attract all the people who've been
trying to send anonymous mail through Tor but couldn't.

> It would be nice if there was a way to specify an additional portlist
> Tor uses to prebuild a couple extra circuits for. Circuit construction
> can take a really long time and maybe this option would help people
> who use apps on ports other than 80 and 443. Roger/Nick,
> agree/disagree? Did I just volunteer? ;)

Well, once you've made a connection to a port, Tor remembers this for
the next hour and tries to prebuild circuits that will allow exits to
that port. But you're suggesting something to give a hint to Tor before
you even do the first connection?

Seems straightforward enough. Another config option, of the same form as
LongLivedPorts, that defaults to "80", maybe called InitialPredictedPorts?
And then see predicted_ports_init() in rephist.c -- replace the third
line with something that parses the smartlist into numbers and adds each
of them.

--Roger