Re: randomness of Tor exit nodes

[alien <alien51@xxxxxxxxxxxx>]

Hi mw,

Saturday, September 10, 2005, 1:09:54 PM, you wrote:

> I've been using Tor for a few weeks now and I've noticed that I don't
> get much randomness in the exit nodes, I've only ever connected through
> about 6 or 7 different ones.  I don't have any restrictions in place
> (except for only using unverified nodes in the middle, which is the
> default setting - everything else is default also).  As I understand it,
> Tor should be picking a random node from a selection of over 200.  
>
> Am I doing something wrong?

Just something to adjust your expectation. Remember that not all
servers exit for a given port. There is only a handful to 119 for
example and even less at a time for email related ports. Second, there
are many middleman nodes (130 or something) so subtract that from your
selection list. And last, once Tor chooses a circuit it will stick
with it for a certain time. This is from the Tor Wiki, notice the last
paragraph for example.

3.7. How often does Tor change its paths?

Tor will reuse the same circuit for new TCP streams for 10 minutes, as
long as the circuit is working fine. (If the circuit fails, Tor will
switch to a new circuit immediately.)

But note that a single TCP stream (e.g. a long IRC connection) will
stay on the same circuit forever -- we don't rotate individual streams
from one circuit to the next. Otherwise an adversary with a partial
view of the network would be given many chances over time to link you
to your destination, rather than just one chance.


-- 
cheers!
 alien  mailto:alien51@xxxxxxxxxxxx

.. Never knock on Death's door. Ring the bell and run!