Redirect loop in ASP.NET app when used in America

I have a bunch of programs written in ASP.NET 3.5 and 4. I can load them fine (I'm in England) and so can my England based colleagues. My American colleagues however are suffering redirect loops when trying to load any of the apps. I have tried myself using Hide My Ass and can consistently recreate this issue.

I'm stumped. What could be causing a redirect loop for users in a specific country?!

The ap开发者_运维知识库ps are hosted on IIS 6 on a dedicated Windows Server 2003. I have restarted IIS with no luck.

Edit

I should have made it clear that unfortunately I do not have access to the machines in the US to run Firefox Firebug/Fiddler. The message I get in Chrome is This webpage has a redirect loop..

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When you say "a redirect loop", do you mean a redirect as in an http redirect? Or do you mean you have a TCP/IP routing loop?

A TCP/IP loop can be positively identified by performing a ping from one of the affected client boxes. If you get a "TTL expired" or similar message then this is routing and unlikely to be application related.

If you really meant an http redirect, try running Fiddler, or even better, HttpWatch Pro and looking at both the request headers, and the corresponding responses. Even better - try comparing the request/response headers from non-US working client/servers to the failing US counterparts

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you could take a look with Live HTTP Headers in firefox and see what it's trying to redirect to. it could possibly be trying to redirect to a url based on the visitor's lang/country, or perhaps the dns is not fully propagated...

if you want to post the url, i could give you the redirect trace

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What could be causing a redirect loop for users in a specific country?!

1. Globalization / localization related code
2. Geo-IP based actions
3. Using different base URLs in each country, and then redirecting from one to itself. For example, if you used uk.example.com in the UK, and us.example.com in the US, and had us.example.com redirect accidentally to itself for some reason.
4. Incorrect redirects on 404 Not Found errors.
5. Spurious meta redirect tags
6. Incorrect redirects based on authentication errors
7. Many other reasons

I have tried myself using Hide My Ass and can consistently recreate this issue.

I have restarted IIS with no luck.

I do not have access to the machines in the US to run Firefox Firebug/Fiddler.

The third statement above don't make sense in light of the other two. If you can restart IIS or access the sites with a proxy, then you can run Fiddler, since it's a client-side application. Looking at the generated HTML and corresponding HTTP headers will be the best way to diagnose your problem.