Open Bug 1056599 Opened 10 years ago Updated 4 days ago

Firefox randomly using IPv6 via 6to4 relay on IPv4 connected client & servers

Categories

(Core :: Networking, defect, P3)

Product:
Core
Component:
Networking
Version:
34 Branch
Platform:
x86_64
Windows 8.1
Type:
defect

Tracking

()

Status:
UNCONFIRMED

People

(Reporter: simon+mozilla, Unassigned, NeedInfo)

References

Details

(Whiteboard: [ipv6][necko-backlog]) 

User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0 (Beta/Release)
Build ID: 20140820030202

Steps to reproduce:

Browse a dual-stack connected website, any Google/Facebook property will do, with a client that has a native IPv4 connectivity only and 6to4 enabled (default in Windows, might need an ISP that runs a relay, though).
Observe in TCPView.


Actual results:

Firefox issues IPv4 and/or v6 connections for the different hosts involved, seemingly at random.


Expected results:

Firefox should prefer the faster, native v4 connection and only fall-back to 6to4 for hosts that are reachable exclusively via v6.

I haven't seen this before today's nightly and it's the first time I show up as logged in from a (2002: prefixed) v6 address on GMail, I'd suspect something to do with https://bugzilla.mozilla.org/show_bug.cgi?id=820391 ?
this is pretty interesting - thanks.

I don't know that I agree with you about the preference issues (I don't know that I disagree with you either :)), but the dns change certainly wasn't expected to have that impact.
Whiteboard: [ipv6]
Blocks: 820391
Whiteboard: [ipv6] → [ipv6][necko-backlog]
Bulk change to priority: https://bugzilla.mozilla.org/show_bug.cgi?id=1399258
Priority: -- → P1
Bulk change to priority: https://bugzilla.mozilla.org/show_bug.cgi?id=1399258
Priority: P1 → P3
Severity: normal → S3
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