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@riseup.net 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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