Re: [tor-relays] Bad experience with hetzner.de and "Trusted Tor Traceroutes" experiment

Hi Alex,

We are very sorry to hear about the problems our measurements caused. Up until yesterday, we had received no reports of them triggering these kinds of responses from providers. However, yesterday we heard a very similar story from another relay operator using Hetzner.

Thanks for sharing your experience with the tor-relays community. We have also updated our FAQ to inform contributors about this potential problem.

Also, we'd like to help others avoid this while still providing useful measurements, if possible. Have you gotten any feedback from Hetzner about what rule was triggered and maybe how to avoid it? Do you have any ideas about how one might stay below their radar? If it is something simple like reducing the measurement rate that would be a great option to prevent problems while still providing valuable data about the the Tor network.

We do still hope that most relay operators will be willing to give this project a shot. We have received data from over 90 separate IP addresses and have gotten 2 negative reports so far, although certainly the issues could be more widespread without us being aware. We don't want to add to the headaches that can result from running a Tor relay, but on the other hand Tor relay operators are probably pretty adept at handling this kind of stuff.

Thanks

Anupam

On Tue, Jan 14, 2014 at 5:02 PM, <irregulator@xxxxxxxxxx> wrote:

Hello there,

We're running a Tor relay (not exit) on a virtual private server at
Hetzner for about a year. On Wednesday January 8th, we decided to take
part in the "Trying Trusted Tor Traceroutes" [1] research experiment.
There have been various calls for participation on public mailing lists
[2] [3].

The traceroutes were conducted using the scamper package, as suggested
in README. We imposed no rate limiting to requests, just run the script
with default values.

Some hours later, Thursday 9th, we received an email from Hetzner
stating that our server was taking part in attacks and they would
suspend our instance if we didn't react within 8 hours. As soon as we
got the warning we killed scamper conducting the traceroutes, and
followed the procedure so as not to get our instance suspended. Hetzner
also asked for some explanations about why we think our server was not
taking part in the attack.

We responded via email with a full explanation about the traceroutes
from our server and the "Trying Trusted Tor Traceroutes" experiment from
various researchers from University of Illinois [1]. We told Hetzner
that our server was making harmless and legal traceroutes to various
destinations on the Internet, thus they had no reason to suspend our
instance.

Twenty four hours later, Friday 10th, Hetzner blocked network access to
the IP address of our server, did send us an email about blocking, but
ignored our exlanations submitted the previous day. After the blockage
of our IP we insisted on trying to resolve the case by sending one more
email exlaining the situation and asking to unblock us, and then opening
a ticket. Hetner's response to the last email (5 hours later) was that
we should open a ticket, which we already had done. Alas, our ticket was
marked as duplicate and closed(?).

During this loophole support nightmare most responses from Hetzner's
part actually seemed to be machine generated. At last Hetzner asked us
via email to send them a signed document via fax(!) containing
explanations about the incident. Now that was ridiculous, since we had
submitted explanations already three times with the first submission
only four hours after Hetzner's first warning on Thursday. Nevertheless,
we did resend the explanation.

After about 7 hours of downtime, Hetzner unblocked network access to our
server. More than 36 hours later they sent an email "Dear Mr. xxxx, your
server is unlocked."

Concluding,

- Hetzner considers traceroutes to various internet destinations as
attack. All relay operators with machines at Hetzner should be _careful_
when taking part in "Trying Trusted Tor Traceroutes" experiment.

- Hetzner has awful customer support.

Cheers,
Alex

[1] https://web.engr.illinois.edu/~das17/tor-traceroute_v1.html

[2]
https://lists.torproject.org/pipermail/tor-relays/2013-October/003113.html

[3] https://lists.torproject.org/pipermail/tor-news/2014-January/000027.html

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