629830 - DNS cache includes lookup failures

Status: RESOLVED DUPLICATE of bug 512969

(Firefox :: General, defect)

Description

[Shad Sterling]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13

Brief connection outages - less than a minute - cause firefox to report a DNS error long after the connection has been restored.  Firefox does not appear to actually attempt to make a connection, the names will resolve e.g. with $(dig), and after killing & restarting firefox pages load as expected.

Reproducible: Sometimes

Steps to Reproduce:
1. Go to a place where no provider offers a reliable connection
2. Use Firefox for something involving a high frequency of requests (watching hulu, google search results, following random links in the same domain)
3. After your connection goes down briefly (and comes back up), watch firefox fail to load new pages on already open domains even though everything else is working.

Actual Results:  
Firefox fails to load or reload certain pages (presumably those where a DNS lookup failed during the outage) for a few minutes

Expected Results:  
Firefox resumes loading pages as usual as soon as the connection is restored

My connection just hiccoughed again, I hope this POST doesn't fail...

Comment 1

[Matthias Versen [:Matti]]

Firefox is using gethostbyname(), are you sure that the OS didn't cache the negative response ?
Did you try to ping instead of dig ?
Probably a dupe of bug 512969

Comment 2

[Shad Sterling]

Since "after killing & restarting firefox pages load as expected" wasn't sufficient:  dig works, ping works, traceroute works, mail works, safari works, chrome works, azureus works, w3m works, ssh works, MobileMe sync works, a new instance of firefox works...  I've never seen any other program continue to be unable to connect after the modem status returns to normal.  So, yes, I'm sure.

It does look like a duplicate of bug 512969, but I'm not familiar enough with Firefox to be sure.  I know Firefox goes into offline mode when I turn off WiFi (but doesn't go back to normal when I turn it back on), so it seems possible that there might be some different connection monitoring mechanism involved.

I failed to note in the description, this affects Firefox 3.6.13 on both OS X 10.6.5 and Windows XP with all available updates.