[tor-dev] What does TorBulkExitList.py return?

[Linus Nordberg]

Hi,

I'm trying to figure out why a list from [TorBulkExitList.py] is so much
larger than what is seen in [exit-addresses].

Point in case: Earlier today the list from TorBulkExitList.py contained
58% more addresses than exit-addresses:

--8<---------------cut here---------------start------------->8---
$ curl-tor -q 'https://check.torproject.org/cgi-bin/TorBulkExitList.py?ip=8.8.8.8' | egrep -v ^# | wc -l
1554
$ curl-tor -q https://check.torproject.org/exit-addresses | egrep ^ExitNode | wc -l
985
--8<---------------cut here---------------end--------------->8---

Counting relays with the Exit flag in a consensus of roughly the same
time gives 912:

--8<---------------cut here---------------start------------->8---
$ curl-tor -q http://171.25.193.9:443/tor/status-vote/current/consensus | egrep '^s.*Exit' | wc -l
912
--8<---------------cut here---------------end--------------->8---


If I read the code [check.py][exitips.py] correctly, we include the
following IP addresses in what is served from [TorBulkExitList.py]:

- all routers in the current consensus
  - with exit addresses from TorDNSEL file(s) added
- for which stem's exit_policy.is_exiting_allowed() returns true

I haven't read any TorDNSEL code and don't know exactly what above
mentioned TorDNSEL file(s) are but I think they include results from
active testing of what address exit relays really use for exiting.

[exit-addresses] seems to be from TorDNSEL too but holding more of a
snapshot while the files mentioned above supposedly cover some period of
time.

Before I dig further, perhaps someone here already know why the numbers
differ so? I wouldn't expect the churn of addresses used for exiting to
be high enough to explain the difference.


[TorBulkExitList.py] https://check.torproject.org/cgi-bin/TorBulkExitList.py?ip=8.8.8.8
[exit-addresses] https://check.torproject.org/exit-addresses
[check.go] https://gitweb.torproject.org/check.git/tree/check.go
[exitips.py] https://gitweb.torproject.org/check.git/tree/scripts/exitips.py

Thanks,
Linus