[tor-relays] Understanding Reduced Exit Policies..?

[Jeremy Olexa]

On Fri, Sep 12, 2014 at 7:46 AM, Moritz Bartl <moritz at torservers.net> wrote:
> Hi Jeremy,
>
> On 09/12/2014 05:02 AM, Jeremy Olexa wrote:
>> My question: If I want to "try" being an exit node and add allowed
>> exit ports slowly, does that help the network or not? For example,
>> month 1: allow port 22, month 2: allow IRC ports, and so-on. How does
>> the client path selection work in this case - is it smart enough to
>> pick my exit when needed?
>
> Yes and no. You can slowly add more ports, but unless you allow port 80,
> 443 and 6667 your relay won't get the Exit flag. [1] Tor clients
> preemptively open some circuits to such exits by default, and will use
> existing circuits unless none of the existing circuits allow the
> destination address or port. So, if you want to help "best", you should
> open at least these three ports. It is a fine strategy to then add more
> and more ports over time, but the other way round is also quite
> reasonable (starting with the Reduced Exit Policy and remove ports on
> complaints).

That is a great idea, thanks for the background info on the Exit flag.
It looks like you need 2 of those 3 ports according to the spec.

>
> The Reduced Exit Policy is most helpful in reducing DMCA complaints for
> Bittorrent traffic: Bittorrent by default picks a random port, and it
> largely reduces the probability of your exit being picked if you just
> allow ~200 instead of 65534 ports.

Makes sense, I'll be experimenting with the exit policy soon.

Thanks,
-Jeremy