Answered by Thomasz
The solution is to add the following to your httpd.conf:
AcceptFilter http none AcceptFilter https none On Windows, this has the effect of disabling the AcceptEx() API (part of WinSock), which offers some performance improvements, but probably conflicts with Comodo Firewall.
Putting Comodo Firewall in "Disabled" mode doesn't help because requests probably still go through Comodo's networking code. I think Comodo would have to be uninstalled completely to eliminate the problem (though I haven't tried it).
If you have a similar problem with Apache 2.2, you should use the Win32DisableAcceptEx directive instead.
References
Quoting from http://httpd.apache.org/docs/2.4/mod/core.html:
The default values on Windows are:
AcceptFilter http data
AcceptFilter https dataWindow's mpm_winnt interprets the AcceptFilter to toggle the AcceptEx() API, and does not support http protocol buffering. There are two values which utilize the Windows AcceptEx() API and will recycle network sockets between connections. data waits until data has been transmitted as documented above, and the initial data buffer and network endpoint addresses are all retrieved from the single AcceptEx() invocation. connect will use the AcceptEx() API, also retrieve the network endpoint addresses, but like none the connect option does not wait for the initial data transmission.
On Windows, none uses accept() rather than AcceptEx() and will not recycle sockets between connections. This is useful for network adapters with broken driver support, as well as some virtual network providers such as vpn drivers, or spam, virus or spyware filters.