一段時間沒有用這個apache，突然之間發現apache不返回東西了，抓包發現不管發什么請求，這個apache總是返回：
Request header field is missing ':' separator
重啟apache，關掉重開，卸掉重裝，折騰半天后還是選擇google了，原來早有人郁悶過這個問題：
http://www.apachelounge.com/forum/viewtopic.php?t=602
Just spent half of night googling.
The main reason that I switched to 2.2.x branch is mod_proxy errors like
"Request header field is missing ':' separator." when accessing sites localhost sites.
Somewhere I read that it might be fixed in 2.2, so that's why I'm here.
After 3 weeks building all neccessary modules putting and tuning all together I see the same error =/
Problem was in Nod32's IMON module. It for some reason duplicates request. I disabled it and all works fine again.
http://issues.apache.org/bugzilla/show_bug.cgi?id=34716
Posting it here to help other with issues like this.
一模一樣的現象，一模一樣的原因。把nod32的imon（也就是網絡監控）禁用了就好了。