Why isn't IIS 7.5 accepting any request with URLs containing the word 'handler'?

Question

We've noticed 2 very weird IIS 7.5 problems running on Windows Server 2008 and ASP.NET 3.5

1. Any requests that contain the word 'handler' result in an HTTP 502.1 error (timeout)
2. Some requests, which we didn't yet identify a possible logic, result in an HTTP 411 error (The request must be chunked or have a content length)

Aditional information:

• The errors only occur when our server is accessed from the internet, outside our network. Everything is fine when the server is accessed internally.

Please help ups, because we found absolutely no help on the internet.

Answer 1

Has this ever worked? When did it stop working? What is your network architecture (any application/network-layer firewalling)? Do you have windows advanced firewall configured, as well (it differentiates between different network segments - but not very well)? Lastly, we had a weird issue that looked similar (the second one) which ended up being related to a window scaling change in Windows 2008 vs. 2003 - so folks coming from inside, e.g. not being "routed" had no issues, but folks from outside, e.g. through router(s) had strange errors/issues. In brief, they no longer set the window size in their tcp packets, but instead effectively set the multiplier in the packet, then send the size to be multiplied in another location. So routers saw the multiplier (very small) and segmented things to the point the connectivity was compromised. I can't find the article I originally worked from but some of this might be helpful:

8help.osu.edu/3253.html www.hkeyusers.com/tcp-window-scaling-autotuninglevel/

Answer 2

502 is a Bad Gateway error. It usually indicates a failure of one web device to talk to another.

That might indicate that there's a reverse proxy or similar between the Internet and your web server, and they're having issues talking to each other.

Sometimes the error will indicate the type of device involved - Apache, ISA Server, or whatever.

The handler problem could indicate a security-related filter on the reverse proxy.

That'd explain why it's only from the Internet that there's a problem, as well.