1704762 - Do not cache negative DNS records for the TRR server domain

Status: RESOLVED FIXED

(Core :: Networking: DNS, defect, P2)

Description

[Valentin Gosu [:valentin]]

(In reply to Valentin Gosu [:valentin] (he/him) from bug 1698321 comment #29)

From the looks of the log it seems that you are using TRR in mode3.
At some point, native DNS fails for reasons that are likely out of our control (maybe the DNS server was down, or the computer went offline)
So there's this line in the log Caching host [mozilla.cloudflare-dns.com] negative record for 60 seconds.

For mode3 we should ensure that a negative record is ignored, so we always retry to get the IP of the TRR server.
In mode2 this is less severe, as we'd fall back to regular DNS, but it's still a 60 period where we might be able to use TRR but don't.

Comment 1

[Valentin Gosu [:valentin]]

Attachment: Bug 1704762 - Add way to specify NXDOMAIN result in NativeDNSResolverOverride r=#necko

Comment 2

[Valentin Gosu [:valentin]]

Attachment: Bug 1704762 - Test that we don't use negative records for the TRR connection r=#necko

Depends on D113355

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9e2d31861565
Add way to specify NXDOMAIN result in NativeDNSResolverOverride r=necko-reviewers,dragana
https://hg.mozilla.org/integration/autoland/rev/a07e32d0f5b3
Test that we don't use negative records for the TRR connection r=necko-reviewers,dragana

Comment 4

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/9e2d31861565
https://hg.mozilla.org/mozilla-central/rev/a07e32d0f5b3