1961459 - typing the URL the page doesn't load "sometime" feel like DNS request failed. Other browser work fine all the time.

Status: RESOLVED DUPLICATE of bug 1964292

(Core :: Networking: DNS, defect)

Description

[Anurag Goyal]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:137.0) Gecko/20100101 Firefox/137.0

Steps to reproduce:

Post entering the URL, the page doesn't load "sometime/intermittently" feel like DNS request failed. Other browser work fine all the time - This is happening on sites like amazon.in.

• This happens randomly on any website. not just above.
• Is there a log that can show what happened.
• I have tried all options on DNS including disable secure DNS but that seems to have no impact. works same for "Default" secure to "off" options.

Actual results:

Site doesn't load. Shows page not found error.

Expected results:

Website should have loaded.

Comment 1

[BugBot [:suhaib / :marco]]

The Bugbug bot thinks this bug should belong to the 'Core::Networking: DNS' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Sunil Mayya]

Thank you Anurag for reporting this bug.

Is there a log that can show what happened.
You can capture http logs.
Please select Networking preset.
If you’re concerned about privacy and prefer not to share the logs through the tool, you can email them directly to [e-mail].

Are you using any kind of proxy in your setup?

Are you observing this issue only in the recent version of firefox? If yes, could you please consider using mozregression to help us narrow down the change that introduced this bug and help us fix quickly.

Comment 3

[Anurag Goyal]

Attachment: log.txt-main.10248.moz_log

Tried opening couple of generic website like amazon.in
or this firefox help page - but it didn't open.

Comment 4

[Anurag Goyal]

I think this is there post upgrade to release FF 137 and further.
I enabled logging and updating the log here.

Are you using any kind of proxy in your setup?
None in my browser, but can be otherwise as not PC.

Comment 5

[Anurag Goyal]

Talking about trying if working with 136, i don't have machine where i can do revert and trials..

Comment 6

[Valentin Gosu [:valentin]]

(In reply to Anurag Goyal from comment #5)

Talking about trying if working with 136, i don't have machine where i can do revert and trials..

Sunil pointed out you can use to try different Firefox versions
https://mozilla.github.io/mozregression/

I've looked at the logs and the first idication of an error is:

2025-04-25 11:31:45.831768 UTC - [Parent 10248: Socket Thread]: D/nsSocketTransport ErrorAccordingToNSPR [in=-5994 out=80004005]
2025-04-25 11:31:45.831770 UTC - [Parent 10248: Socket Thread]: D/nsSocketTransport   connection failed! [reason=80004005]
2025-04-25 11:31:45.831782 UTC - [Parent 10248: Socket Thread]: D/nsHostResolver Adding address to blocklist for host [firefox-source-docs.mozilla.org], host record [154828310].used trr=0
2025-04-25 11:31:45.831785 UTC - [Parent 10248: Socket Thread]: D/nsHostResolver Successfully adding address [2600:9000:24d8:e400:f:7257:3ec0:93a1] to blocklist for host [firefox-source-docs.mozilla.org].

Following this error, the IP is added to the blocklist, since connecting failed.
Does this happen on other machines?
Do you have any Firewalls, anti-virus applications or something else that might affect networking on your machine or in your network?

Can you check if setting network.dns.disableIPv6 to true in about:config fixes the issue?
It's possible that there are issues with IPv6 on your network, and failures only occur for IPv6 addresses.

Comment 7

[Anurag Goyal]

Yes, network.dns.disableIPv6 to true in about:config fixes the issue.
how to know what exactly the issue.

Comment 8

[Anurag Goyal]

But how come other browser work all the time? but Firefox shows no page load like mentioned above.

Comment 9

[Kershaw Chang [:kershaw]]

Based on the log in comment #3, I think this is the same as bug 1964292.