tor-relays January 2022

tor-relays@lists.torproject.org

47 participants
30 discussions

How to reduce tor CPU load on a single bridge?
by David Fifield 19 Dec '22

19 Dec '22

The main Snowflake bridge (https://metrics.torproject.org/rs.html#details/5481936581E23D2D178105D44DB6…) is starting to become overloaded, because of a recent substantial increase in users. I think the host has sufficient CPU and memory headroom, and pluggable transport process (that receies WebSocket connections and forwards them to tor) is scaling across multiple cores. But the tor process is constantly using 100% of one CPU core, and I suspect that the tor process has become a bottleneck. Here are issues about a recent CPU upgrade on the bridge, and observations about the proportion of CPU used by different processes: https://bugs.torproject.org/tpo/anti-censorship/pluggable-transports/snowfl… https://bugs.torproject.org/tpo/anti-censorship/pluggable-transports/snowfl… I have the impression that tor cannot use more than one CPU core—is that correct? If so, what can be done to permit a bridge to scale beyond 1×100% CPU? We can fairly easily scale the Snowflake-specific components around the tor process, but ultimately, a tor client process expects to connect to a bridge having a certain fingerprint, and that is the part I don't know how to easily scale. * Surely it's not possible to run multiple instances of tor with the same fingerprint? Or is it? Does the answer change if all instances are on the same IP address? If the OR ports are never used? * OnionBalance does not help with this, correct? * Are there configuration options we could set to increase parallelism? * Is migrating to a host with better single-core performance the only immediate option for scaling the tor process? Separate from the topic of scaling a single bridge, here is a past issue with thoughts on scaling beyond one bridge. it looks as though there are not ways to do it that do not require changes to the way tor handles its Bridge lines. https://bugs.torproject.org/tpo/anti-censorship/pluggable-transports/snowfl… * Using multiple snowflake Bridge lines does not work well, despite that we could arrange to have the Snowflake proxy connect the user to the expected bridge, because tor will try to connect to all of them, not choose one at random. * Removing the fingerprint from the snowflake Bridge line in Tor Browser would permit the Snowflake proxies to round-robin clients over several bridges, but then the first hop would be unauthenticated (at the Tor layer). It would be nice if it were possible to specify a small set of permitted bridge fingerprints.

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relayor v22.0.0-rc is released
by nusenu 03 Dec '22

03 Dec '22

Hi, relayor v22.0.0-rc is released. relayor is an ansible role that helps you with running tor relays with minimal effort (automate everything). https://github.com/nusenu/ansible-relayor#main-benefits-for-a-tor-relay-ope… Changes since relayor v21.2.0-rc: * MetricsPort support improvements: * generate nginx reverse server config for remote prometheus scraping on the relay (we do not install nginx) * generate htpasswd file for HTTP basic auth of MetricsPort on the relay * debian/ubuntu: support new alpha repos (branch name is no longer included in the repo name). * FreeBSD 12.3 is supported kind regards, nusenu -- https://nusenu.github.io

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Loss of Guard and HS Dir flags
by Eddie 29 May '22

29 May '22

I currently run 3 relays, across different servers and today I noticed that one has now lost it's Guard and HS Dir flags. What's surprising is that this particular relay has the highest Bandwidth and Consensus Weight of all 3 and has not been restarted for over a month. The stats for all 3 can be found with: OhNoAnotherRelay I know that just running the relay is the important part and caring about what flags it has is a side issue, but I'm just interested in seeing why this has happened. Cheers.

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Ansible role to deploy Bridges
by Erasme - Relay Operator 09 Mar '22

09 Mar '22

Hi all, In the effort of deploying obfs4 bridges for the community we are sharing our Ansible role that allowed us to deploy multiple nodes: https://github.com/NewNewYorkBridges/ansible-tor-bridge For now it is only available on Debian but we will make it available for other distributions. We hope this role is helpful for the community. Feel free to send us your feedback! Kind regards, Erasme

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cases where relay overload can be a false positive
by s7r 07 Feb '22

07 Feb '22

Hello, One of my relays (guard, not exit) started to report being overloaded since once week ago for the first time in its life. The consensus weight and advertised bandwidth are proper as per what they should be, considering the relay's configuration. More than this, they have not changed for years. So, I started to look at it more closely. Apparently the overload is triggered at 5-6 days by flooding it with circuit creation requests. All I can see in tor.log is: [warn] Your computer is too slow to handle this many circuit creation requests! Please consider using the MaxAdvertisedBandwidth config option or choosing a more restricted exit policy. [68382 similar message(s) suppressed in last 482700 seconds] [warn] Your computer is too slow to handle this many circuit creation requests! Please consider using the MaxAdvertisedBandwidth config option or choosing a more restricted exit policy. [7882 similar message(s) suppressed in last 60 seconds] This message is logged like 4-5 or 6 time as 1 minute (60 sec) difference between each warn entry. After that, the relay is back to normal. So it feels like it is being probed or something like this. CPU usage is at 65%, RAM is at under 45%, SSD no problem, bandwidth no problem. Metrics port says: tor_relay_load_tcp_exhaustion_total 0 tor_relay_load_onionskins_total{type="tap",action="processed"} 52073 tor_relay_load_onionskins_total{type="tap",action="dropped"} 0 tor_relay_load_onionskins_total{type="fast",action="processed"} 0 tor_relay_load_onionskins_total{type="fast",action="dropped"} 0 tor_relay_load_onionskins_total{type="ntor",action="processed"} 8069522 tor_relay_load_onionskins_total{type="ntor",action="dropped"} 273275 So if we account the dropped ntor circuits with the processed ntor circuits we end up with a reasonable % (it's >8 million vs <300k). So the question here is: does the computed consensus weight of a relay change if that relay keeps sending reports to directory authorities that it is being overloaded? If yes, could this be triggered by an attacker, in order to arbitrary decrease a relay's consensus weight even when it's not really overloaded (to maybe increase the consensus weights of other malicious relays that we don't know about)? Also, as a side note, I think that if the dropped/processed ratio is not over 15% or 20% a relay should not consider itself overloaded. Would this be a good idea? Sending to tor-relays@ for now, if some of you think of this in any way we can open a thread about it on tor-dev@ - please let me know if I should do this.

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Outdated GeoIP DB
by Martin Gebhardt (Die LINKE.) 06 Feb '22

06 Feb '22

Hi, in the past I had already written with someone about it. At that time the entries were not up to date. There was a Gitlab issue about this, but I can't find it now. Anyway, the data is not up to date again. Example: https://apps.db.ripe.net/db-web-ui/query?searchtext=89.58.17.76 vs https://metrics.torproject.org/rs.html#details/6A0A9C3B3381C89CCB85C64BBCF6… The IP address is currently located in Austria. But in the metrics Germany is displayed. This is a "correct" but outdated information. Since I don't know if this can have any effects on the routing, which I don't assume, but is theoretically possible, I just want to target it again.

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Relay operators meetup @ FOSDEM
by Stefan Leibfarth 04 Feb '22

04 Feb '22

Greetings relay operators, the next Tor relay operators meetup will be online @ FOSDEM. Date: 2022-02-05 Time: 1500 UTC Room: https://lecture.senfcall.de/rin-2tx-xcy-g5r No need for a registration or anything else, just use the room-link above. There will be a agenda, but everyone is free to bring up additional questions or topics at the meeting itself. Looking forward to meeting you Leibi [0] https://fosdem.org/2022/fringe/

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reminder: tor 0.3.5 reaches end of life on 2022-02-01
by nusenu 01 Feb '22

01 Feb '22

Reminder: tor 0.3.5 reaches it's end of life on 2022-02-01 (in 3 weeks from now). Over 700 relays - about 7% of the network's guard capacity currently still run this soon unsupported tor version. https://gitlab.torproject.org/tpo/core/team/-/wikis/NetworkTeam/CoreTorRele… kind regards, nusenu -- https://nusenu.github.io _______________________________________________ tor-relays mailing list tor-relays(a)lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays

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OVHcloud does not allow Tor exit relays on VPS/cloud services
by Neel Chauhan 01 Feb '22

01 Feb '22

Hi, I was running a pair of Tor exit relays on OVH, and when I sent an response, I got this as a reply: === As provided in our Service Specific Terms, Anonymization services, such as TOR, are not permitted on OVHcloud's VPS or Public Cloud services. We request that you immediately cease utilizing your current subscriptions as a TOR exit node. Failure to comply with this request may result in the suspension and/or termination of your servers and/or account in accordance with our Terms of Service. https://us.ovhcloud.com/legal/service-specific-terms === It seems OVH does not allow Tor exit relays on "cloud" or "VPS" subscriptions anymore. In the past when I used OVH for exits I had no issues, so they must have changed their TOS. I am assuming OVH dedicated servers are fine. I guess I'm moving the two exit relays to Terrahost. Terrahost is more expensive but I already have exits there and they are excellent. I never had a great experience with OVH. -Neel

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wrong iptables rules? / no inbound traffic in nyx
by ax8eaz7z3g 27 Jan '22

27 Jan '22

Hi! I noticed that after I have set up my ip(+6)tables up to filter unwanted incoming traffic all "inbound" and "directory" connections in nyx disappeared, only lot of "outbound" connections are there. I am running exit relay (IPv4+IPv6) on ORPort 443 and DIRPort 80. Is there someone willing to check my iptable rules? I am starting to lose it... > My iptables: > -P INPUT DROP > > -P FORWARD DROP > > -P OUTPUT DROP > > -A INPUT -i lo -j ACCEPT > > -A INPUT -p tcp -m conntrack --ctstate NEW,ESTABLISHED -m tcp --dport 22 -j ACCEPT # SSH running there > > -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT # allow incoming comm to ORPort > > -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT # allow incoming comm to DIRPort > > -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT # allow all already established incoming connections > > -A OUTPUT -o lo -j ACCEPT # allow all outgoing connections > > -A OUTPUT -o eth0 -j ACCEPT > My ip6tables: > > -P INPUT DROP > > -P FORWARD DROP > > -P OUTPUT DROP > > -N ICMPv6_IN > > -N ICMPv6_OUT > > -A INPUT -i lo -j ACCEPT > > -A INPUT -p tcp -m conntrack --ctstate NEW,ESTABLISHED -m tcp --dport 22 -j ACCEPT # SSH running there > > -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT # allow incoming comm to ORPort > > -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT # allow incoming comm to DIRPort > > -A INPUT -p ipv6-icmp -j ICMPv6_IN #pass all icmpv6 related traffic to new chain > > -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT # allow all already established incoming connections > > -A OUTPUT -o lo -j ACCEPT > > -A OUTPUT -p ipv6-icmp -j ICMPv6_OUT #pass all icmpv6 related traffic to new chain > > -A OUTPUT -o eth0 -j ACCEPT # allow all outgoing connections > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 1 -j ACCEPT > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 2 -j ACCEPT > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 3 -j ACCEPT > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 4 -j ACCEPT > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 128 -j ACCEPT > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 129 -j ACCEPT > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 133 -j ACCEPT > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 134 -j ACCEPT > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 135 -j ACCEPT > > -A ICMPv6_IN -p ipv6-icmp -m icmp6 --icmpv6-type 136 -j ACCEPT > > -A ICMPv6_IN -j DROP > > -A ICMPv6_OUT -p ipv6-icmp -m icmp6 --icmpv6-type 128 -j ACCEPT > > -A ICMPv6_OUT -p ipv6-icmp -m icmp6 --icmpv6-type 129 -j ACCEPT > > -A ICMPv6_OUT -p ipv6-icmp -m icmp6 --icmpv6-type 133 -j ACCEPT > > -A ICMPv6_OUT -p ipv6-icmp -m icmp6 --icmpv6-type 134 -j ACCEPT > > -A ICMPv6_OUT -p ipv6-icmp -m icmp6 --icmpv6-type 135 -j ACCEPT > > -A ICMPv6_OUT -p ipv6-icmp -m icmp6 --icmpv6-type 136 -j ACCEPT > > -A ICMPv6_OUT -j DROP Thank you all for any replies! Have a nice day. Bye

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tor-relays January 2022