Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

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

we have an ASP.NET 4 website deployed on two nearly identical VirtualBox VMs with IIS 7.5. They are both hosted on the same Ubuntu system with Apache 2.2.14.

Apache decides by hostname ( or to which VM the query is sent. It has two VirtualHosts with ProxyPass/ProxyPassReverse configured and selects the VM by it's IP (the VMs are connected by VirtualBox's "Host-only" virtual network adapter to the host).

This setting works fine, except that some requests do not finish. The browser tries to download the file (e.g. a static JS file) for exactly 5 minutes, when Apache returns a 502 Proxy Error result. Apache logs say that IIS didn't respond in time. In IIS logs the request doesn't even appear.

Any hints where to look for these occasional errors? Apache? VirtualBox virtual network adapter? IIS?

Excerpt of Apache VirtualHost config:


ProxyRequests off
ProxyPreserveHost On

<Proxy *>
allow from all

ProxyPass /
ProxyPassReverse /
share|improve this question
up vote 0 down vote accepted

We use this when proxying to IIS via Apache:

<Location />
        SetEnv force-proxy-request-1.0 1
        SetEnv proxy-nokeepalive 1
share|improve this answer
Thanks, I will try these settings and check if it changes for the better! – Tarnschaf Sep 22 '11 at 12:29
No problems since I added those config lines. Thanks! – Tarnschaf Sep 26 '11 at 21:20

Your Answer


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

Not the answer you're looking for? Browse other questions tagged or ask your own question.