Firefox redirect delay with https and gzip




12 years ago
9 years ago


(Reporter: per, Unassigned)


2.0 Branch

Firefox Tracking Flags

(Not tracked)


(Whiteboard: [CLOSEME 5-15-2010])



12 years ago
User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/20061208 Firefox/
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/20061208 Firefox/

Location header (301/302) makes firefox hang for 1-12 seconds before going to the redirected page. This only occurs when using gzip content encoding on ssl encrypted pages (https). This is very annoying since many systems issue a redirect after each POST.

Using live headers, I can clearly see that the delay is on the client side. Firefox receives the following headers (example from ssh encrypted squirrelmail login page):
HTTP/1.x 302 Found
Date: Sat, 03 Feb 2007 14:18:44 GMT
Server: Apache/2.2.4 (Unix) mod_ssl/2.2.4 OpenSSL/0.9.7e PHP/4.4.4
X-Powered-By: PHP/4.4.4
Location: src/login.php
Vary: User-Agent,Accept-Encoding
Content-Encoding: gzip
Content-Length: 20
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/html

After this the delay 1 up to 12 seconds occur before firefox issues "
GET /src/login.php HTTP/1.1".

If I disable gzip (mod_deflate) on the webserver the problem disappears. The certificate is issued by our own certificate authority, and the CA-certificate is installed in the browser. 

The problem is not present in firefox 1.0 or 1.5, or other mozilla based browsers like epiphany and galeon. On windows, firefox 2 does not have this problem.

I have observed this behaviour on debian sarge and debian etch (clean firefox installation with new profile and no extensions). The is also an observation from ubuntu at

Reproducible: Always

Comment 1

12 years ago
I reported very similar bug. See Bug 368179. I am using mod_deflate too. But when I this module disable this bug for me exist still.

Comment 2

12 years ago
I have noticed the same issue in Firefox and, but it works fine in  When I monitor my logs, I notice that when I sign in to my page, Firefox makes a request to /signin.php and receives a 302 response immediately.  It then waits 1 to 15 seconds before issuing an HTTP request for the /index.php page that it was redirected to.

I also am using mod_deflate over SSL.

I've had this happen on my Mac Firefox, Windows Firefox, and Linux Firefox (Ubuntu and Gentoo).  Currently as a workaround, I'm using version  Man, I'm so happy somebody else noticed this problem too.  I thought I was going crazy for a while there.

Comment 3

12 years ago
I'm also seeing this on Gentoo Linux with the binary (official) Firefox. I put a testcase up at

Firefox still displays this behavior on Linux; 1.0.8/ on Linux, and a 2.0.0.x on Windows does not.

Comment 4

11 years ago
Firefox 3beta5 Linux is ok.

Comment 5

10 years ago
I'm having this problem on Win XP with Firefox 3.0.10 (without any add-ons), against Apache2 without mod_deflate/gzip. 

It does not matter whether I use 301, 302 or 303 redirects.

It happens only with Firefox and https (20-40% of the redirects hang for 6-12s). Without https and with other browsers (IE, Safari, Opera, Chrome) I don't see this happening.

Comment 6

10 years ago
Interestingly, I do *not* have this problem if I run Firefox 3.0.10 on an Ubuntu 8.10 VM on the same Win XP computer.

Comment 7

10 years ago
Another observation: If I set the priority of the Firefox process to high on Windows, I can make the problem go away, and if I use renice to lower the priority of the Firefox process on Ubuntu, I can provoke the problem here, too.

Comment 8

10 years ago
I have opened a new Bug 399981 for this problem happening on Windows XP and without gzip.

Comment 9

10 years ago
Sorry - the issue on Windows XP one is Bug 491153.

Comment 10

9 years ago
This is a long standing issue, reported by me on Launchpad:

as reported there, it seems to have become more severe with FF3.5.

Anyone interested in working on this with me?


9 years ago
This bug was reported on Firefox 2.x or older, which is no longer supported and will not be receiving any more updates. I strongly suggest that you update to Firefox 3.6.3 or later, update your plugins (flash, adobe, etc.), and retest in a new profile. If you still see the issue with the updated Firefox, please post here. Otherwise, please close as RESOLVED > WORKSFORME
Whiteboard: [CLOSEME 5-15-2010]
Version: unspecified → 2.0 Branch

Comment 12

9 years ago
just retested with FF3.6.3 Kubuntu 10.04 lighttpd 1.4.26 and php 5.2.10.

I CANNOT redproduce this currently. Hoping finally fixed in FF3.6 (since it was still occurring in FF3.5).


9 years ago
Last Resolved: 9 years ago
Resolution: --- → WORKSFORME

Comment 13

9 years ago
I can confirm that the similar Bug 491153 still exists in FF 3.6.3, so I fear this one isn't really fixed either. It's just hard to reproduce since it seems to be a multitasking timing issue depending on the OS, hardware and what's currently running on the machine. I have set up a test page for Bug 491153 on my webserver so you can easily check if it happens on different machines.
we'll dupe to bug 491153 then, more recent
Duplicate of bug: 491153
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