Our development team has built a WebApp witch purpose is to select a location on a map.

there is a UserControl that was developed in ASP.Net 2.0 and it works fine if the application is accessed directly by the browser, but if the browser is set up to use a proxy server, all loads fine except the Maps.

the maps are being rendered by a product called ASPmap by vdstechnology.

i'm clueless of what could cause this behavior, but i have found out looking at the Request and reponses fron the server that, they are different when you use a Proxy.

what change is the following:

No Proxy Used: Full SizeNo Proxy

Whit Proxy:Full Size With Proxy

As you can see the headers with no proxy uses relatives requests and whit the proxy it uses the full URL.

Could this be the problem? or what else could i do to diagnose why is this happening.

BTW, this behavior was reported to us by a client that uses ISA server. and i have replicated the issue using our squid proxy server.

thanks very much for your time and ill apreciate any insights or pointers that could lead me to the solution


Could it be a performance issue (delay because of proxy server)?

  • No, all other websites work ok – Hugo Garcia Dec 14 '10 at 14:31

Community poked this with a stick, so...

What I think you're seeing there are the headers that the client sends to the proxy. When a client talks to a proxy, it always makes a fully-qualified request; when the proxy talks to the back-end server, it will typically translate that back down to relative requests.

Getting a simultaneous Netmon/Wiresharek capture from the client and server side will help understand the behaviour better - it could be that the extra headers introduced by the proxy (Via for example) cause problems with assumptions about header order or contents in the client AJAX component, unless both proxies are upset at some aspect of the server-side response and are "protecting" the client.

  • Thanks very much Tristan, i will do some sniffing on both sides of the pipe to understand better the behavior, and will focus on what headers changes on a direct request and the one made by the proxy server. Im glad you took your time to explain to me the proxy behavior. something new that i learned. – Hugo Garcia Mar 25 '11 at 13:06

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