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Apache is returning rare intermittent 400 "bad request header field is missing ':' olhuaqv3o1t29flvr0 (random string)" errors. This seems to be related to https access and happens from Firefox, IE, Chrome etc. I am using a certificate from rapidssl.

Apache/2.2.14 (Ubuntu) DAV/2 SVN/1.6.6 mod_jk/1.2.28 PHP/5.3.2-1ubuntu4.5 with Suhosin-Patch mod_ssl/2.2.14 OpenSSL/0.9.8k

Anyone know how to fix this?

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We are having the same problem, and from what I can tell it is almost certainly not directly related to the client. We run a premium web app, and I've had reports of about 20 users having this issue today. They are using a mixture of Win/Mac platforms, some with corporate networks/some without, etc. Lots of client variety. I can't reproduce the problem and we're desperate to know what might be causing it. Our server config is very similar but instead of PHP we are using Apache Tomcat behind our Apache web server. – pakeha Jan 31 '11 at 22:15
At the risk of "me too", I have the same issue on Fedora 13/Apache 2.2.16. Seems unreproducable and has only started happening in the past week or so. Did you find a solution for this? – richsage Feb 24 '11 at 12:40
No luck with a solution. I am also using Apache Tomcat btw. – David Tinker Aug 18 '11 at 13:48

I was having this problem with apache 2.2.9 and upgrading to apache 2.2.22 solved the problem for me.

I would get random 400 response codes on some of the page requests. Sometimes images, sometimes AJAX requests. Occasionally it would be the page itself that would return a 400 along with this message.

Bad Request Your browser sent a request that this server could not understand. Request header field is missing ':' separator. live

I found the following bug report for that seemed related. The bug was fixed in apache 2.2.15 :

I think this bug is the cause for lots of random errors when using https: Your browser sent a request that this server could not understand Request header field is missing ':' separator.

So thought I'd try updating to the latest apache - and that seemed to work.

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If you're using Windows as your client computers, you can try fiddler (

It seems like a Http protocol violation, as I've been experimenting with http(s) proxies recently, and have seen quite a lot of similar untraceable errors. It doesn't seem like the problems of the browser or Apache, so consider the possibility for unstable internet connection if you're testing remotely.

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I have see the error from both Windows (IE7) and Mac OS X (Chrome and Firefox) so I don't think it is client related. It may be a proxy issue however. – David Tinker Jan 24 '11 at 14:00

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