Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a Windows Server 2008 R2 SP1 box with IIS 7.5.7600.16385 installed.

I have HTTP Keep-Alives switched off. Each time a web-request is made the connection is terminated.

I get the following packet trace:

enter image description here

I can see a FIN,ACK going from the client to the server, but none transmitted in the opposite direction.

If I try this from other machines with a supposedly identical configuration the FIN, ACK is transmitted in both directions.

I can't work out what the difference is? Is there any way of configuring this behaviour?

share|improve this question
Does the symptom present when HTTP keep-alive is enabled? – Greg Askew Jan 24 '13 at 12:13
No - because the connections aren't closed. If I forcibly exit the process I get a RST transmitted by the application. – Simon Johnson Jan 24 '13 at 12:57
Seems like you may have answered your own question. Why are you disabling HTTP keep alive? If you want to mitigate the performance impact of connection and resource exhaustion, lower the connection timeout. Apache for example, uses a timeout of 15 seconds, compared to IIS default timeout of 120 seconds. – Greg Askew Jan 24 '13 at 13:12
Check the flags on the "Application Data" packet, it will most likely have the missing FIN/PSH/ACK flags. – Joachim Isaksson Dec 4 '13 at 20:09

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.