Opened 2 years ago

Last modified 7 days ago

#24014 new enhancement

Make exits check DNS periodically, and disable exit traffic if it fails

Reported by: teor Owned by:
Priority: Medium Milestone: Tor: unspecified
Component: Core Tor/Tor Version:
Severity: Normal Keywords: tbb-performance, tbb-usability, performance, tbb-needs, 034-triage-20180328, 034-removed-20180328, network-health
Cc: gk, brade, mcs, arthuredelstein Actual Points:
Parent ID: Points: 1
Reviewer: Sponsor:

Description

Currently exits check once at startup, which doesn't detect overloaded DNS servers once the exit receives significant traffic.

See #21394 for details,

Since this is a new feature, it is not going to make it into 0.3.2.

Child Tickets

TicketTypeStatusOwnerSummary
#26691enhancementnewadd 'working DNS' to the list of mandatory requirements for the 'exit' flag

Attachments (1)

20191220_top60exit_inc_100dns-fail.zip (35.9 KB) - added by starlight 4 weeks ago.
top 60 exit as-of ticket with 8 at 100% dns fail

Download all attachments as: .zip

Change History (16)

comment:1 Changed 2 years ago by arthuredelstein

Cc: arthuredelstein added

comment:2 Changed 2 years ago by teor

Parent ID: #21394

Parent ticket is done

comment:3 Changed 2 years ago by nickm

Milestone: Tor: 0.3.3.x-finalTor: 0.3.4.x-final
Type: defectenhancement

Label a bunch of (arguable and definite) enhancements as enhancements for 0.3.4.

comment:4 Changed 2 years ago by cypherpunks

Shouldn't we check not only 80 and 443 ports, but DNS requests as well, and without relying on exits?

comment:5 in reply to:  4 Changed 2 years ago by teor

Replying to cypherpunks:

Shouldn't we check not only 80 and 443 ports, but DNS requests as well, and without relying on exits?

This ticket is about exits checking that their DNS is still working on a regular basis.
It has nothing to do with ports 80 and 443.

comment:6 Changed 2 years ago by cypherpunks

This is a great feature!
As a tor exit operator I'd like to have a switch that allows me to say "if DNS fails terminate tor" (not just "disable exiting") because this will make it easier for my monitoring to pick it up.

Last edited 2 years ago by cypherpunks (previous) (diff)

comment:7 Changed 22 months ago by nickm

Keywords: 034-triage-20180328 added

comment:8 Changed 22 months ago by nickm

Keywords: 034-removed-20180328 added

Per our triage process, these tickets are pending removal from 0.3.4.

comment:9 Changed 22 months ago by nickm

Milestone: Tor: 0.3.4.x-finalTor: unspecified

These tickets, tagged with 034-removed-*, are no longer in-scope for 0.3.4. We can reconsider any of them, if time permits.

comment:10 Changed 19 months ago by arthuredelstein

Keywords: tbb-wants added

comment:11 Changed 19 months ago by teor

Keywords: tbb-wants removed

Prefer the more common tbb-needs to tbb-wants.
There doesn't appear to be any difference in how much TBB needs based on the flag.

comment:12 Changed 4 weeks ago by starlight

Duplicate ticket #32828 was opened on 2019/12/20 more than two years after this one--so much times has passed this was forgotten:

Large numbers of exit relays with 100% DNS failure rates frequently appear on ​https://arthuredelstein.net/exits/, which by itself has proven insufficient motivation for exit operators to assure functional DNS. Enhance tor daemon to automatically disable the exit policy and fallback to not-exit operation when DNS failure rates exceed a threshold for a time.

comment:13 Changed 4 weeks ago by starlight

also

For avoidance of doubt regarding the importance of this issue, attached top sixty exits by exit_probability as-of the creation of this ticket, where eight of the sixty exhibit 100% DNS failure rate.

Changed 4 weeks ago by starlight

top 60 exit as-of ticket with 8 at 100% dns fail

comment:14 Changed 4 weeks ago by starlight

and

The purpose of the feature is not to remove bandwidth (note the idea is only to disable the exit policy), but rather is to improve user experience and pointedly motivate exit operators to complete the straightforward task of proper DNS configuration. For detailed background and rationale see #21394. Automatic enforcement of functional exit DNS will lighten the burden on thinly-stretched volunteer and staff Tor Project resources.

comment:15 Changed 7 days ago by gk

Keywords: network-health added
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