[tor-dev] connectivity failure for top 100 relays

teor teor2345 at gmail.com
Tue Mar 13 07:43:49 UTC 2018

> On 13 Mar 2018, at 03:55, dawuud <dawuud at riseup.net> wrote:
> Out of 9900 possible two hop tor circuits among the top 100 tor relays
> only 935 circuit builds have succeeded. This is way worse than the last
> time I sent a report 6 months ago during the Montreal tor dev meeting.

How much worse?

And where did you scan *from*?
(It's hard to interpret the results without the latency and quality of your
client connection.)

Also, we have just deployed defences to exactly this kind of rapid circuit
or connection building by a single client. I wonder if your client triggered
those defences. The circuit defences would likely cause timeouts, and
the connection defences would likely cause failures.

I also wonder if your client triggered custom defences on some relays.

> Here's the scanner I use:
> https://github.com/david415/tor_partition_scanner
> Here's the gist of my simple testing methodology:
> https://gist.github.com/david415/9875821652018431dd6d6c4407bb90c0#file-detect_tor_network_partitions
> Here's exactly how I performed the scan to get those results:
> wget https://collector.torproject.org/recent/relay-descriptors/consensuses/2018-03-13-01-00-00-consensus
> ./helpers/query_fingerprints_from_consensus_file.py 2018-03-1
> 3-01-00-00-consensus > top100.relays
> detect_partitions.py --tor-control tcp: --log-dir ./ --status-log ./status_log \
>   --relay-list top100.relays --secret secretTorEmpireOfRelays --partitions 1 --this-partition 0 \
>   --build-duration .25 --circuit-timeout 60 --log-chunk-size 1000 --max-concurrency 100

You might get better results if you scan more slowly.
Try to stay under 1 circuit every 3 seconds to each relay from
your IP address. Try to stay under 50 connections to the same
relay from your IP address.

I'm going from memory, check the Tor man page, dir-spec, and
the consensus for the latest DDoS parameter values.


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