[metrics-bugs] #32473 [Metrics/Exit Scanner]: Evaluate the results from the exitmap based scanner compared to the current exit lists system

Tor Bug Tracker & Wiki blackhole at torproject.org
Wed Nov 27 18:11:17 UTC 2019


#32473: Evaluate the results from the exitmap based scanner compared to the current
exit lists system
----------------------------------+------------------------------
 Reporter:  irl                   |          Owner:  metrics-team
     Type:  task                  |         Status:  new
 Priority:  Medium                |      Milestone:
Component:  Metrics/Exit Scanner  |        Version:
 Severity:  Normal                |     Resolution:
 Keywords:                        |  Actual Points:
Parent ID:                        |         Points:
 Reviewer:                        |        Sponsor:
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Comment (by irl):

 Replying to [comment:3 karsten]:
 > I compared those exit lists from the new exit scanner (only 2019-11-26
 or later) to the ones published by the old exit scanner from the same time
 frame. I attached my output file that organizes scan results by
 fingerprint. Some observations:
 >
 >  - The new scanner omits a handful relays that the old scanner scanned.
 I assume this is related to exit policies? The absolute number of these
 cases is rather low, but please take a look, too (at the beginning of the
 output file).

 These are all exit policy related. The current implementation requires
 port 443 to be allowed. A future version, with the help of TSA and
 iptables, could work around this limitation. It looks like the current
 scanner starts a listener on port 80 but I don't know Haskell enough to
 understand what it is doing.

 >  - The vast majority of scans (over 1,000) result in the same exit
 address. There are just 6 relays with 2 or more exit addresses by either
 old or new scanner. It's hard to say which scanner is right here. Maybe
 it's just relays on dynamic IPs or with multiple IP addresses. Please take
 a look at these (grep for "exit addresses total").

 These look like dynamic IPs, I can't see anything that would suggest
 otherwise.

 >  - Looks like the new scanner doesn't properly clear old scan results.
 I'm only looking at results from 2019-11-26 and later, and yet there are
 scan results from 2019-11-19 and 2019-11-20. This seems like a (small)
 bug.

 Yes, I'd disabled that to test merging with an older file, I'll uncomment
 that code again. (:

 > That's all. Overall, I think that these results are as close to the
 current scanner as they can get. If we can resolve that one bug and get
 your confirmation that the other two things are normal, I think we're good
 to go.

 Awesome!

 I will hopefully wrap up #32264 tonight and then #32265 tomorrow, and then
 deploy to AWS over the weekend to evaluate again before asking TPA for a
 machine.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/32473#comment:4>
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