Get original HOST address when the ASP.NET server is behind an ISA server as a reverse proxy

I'd like to know how could I get the origin开发者_运维百科al HOST IP when the web server is behind an ISA server acting as a reverse proxy.

Other reverse proxies -like squid- add the "X_FORWARDED_FOR" value to the request header, but ISA server doesn't.

Thanks

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I am not familiar with ISA, but with a solution at my employer we had the proxy set up a custom header and we retrieved it from there. Nothing was set by default, we had to specifically request that something was sent in.

If this is not possible on ISA, then you are out of luck.

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Cannot get. Use hostname instead of it.