problems with url in asp.net application.

Hello
I am all new to .Net. I have an asp.net applicaton. my boss says when i publish the application and launch on clients system the URL should not contain .aspx extension. I have never done this before.I really dont know how to do this. the url shouldnot contain .aspx extension...plzz help me how do i do it...remember m all ne so if u can explain me in detail plzz...
I will be really thankful 2 u
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