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I have two servers on my network both are running Windows server 2008 r2 and both are using IIS 7.

I currently have the subdomain pointing to our external IP ( and then ports 80 and 443 forwarded to the exchange mail server ( I would like to have pointing to the same external IP ( but have ports 80 and 443 forwarded to a different web server ( Is there away to do this either through IIS, DNS or my router(Cisco ASA-5505)?

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A router or firewall can't do what you want, because it only handles TCP/IP traffic, and thus can only forward a given port to a given internal server; what you need is a reverse proxy, which, being able to understand HTTP(S) requests, can forward them to the right web server based on host headers. Microsoft TMG is a product which will happily perform this task.

However, if you are using HTTPS, things will get a little more complex, because only a given SSL certificate can be bound to a given IP address/port pair, so you will need a certificate capable of accepting both names.

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That is just making things unneccessarily complicated, instead of just buying another IP. – Frederik Nielsen Sep 17 '12 at 18:31
@FrederikNielsen it does answer the question, though. – MDMarra Sep 17 '12 at 18:32
@MDMarra True, but it is still over complicating things :) Thats also why I didn't downvote it. It is a solution, but not the best. – Frederik Nielsen Sep 17 '12 at 18:33
@FrederikNielsen, I totally agree. But this is what the OP asked for, so I answered it :-) – Massimo Sep 17 '12 at 18:33
You just need a reverse proxy that supports SNI, and for whoever is coming to your web site to not be using IE on Windows XP. – Michael Hampton Sep 17 '12 at 18:38


You cannot forward the same ports to multiple destinations - that is simply not possible.

You would have to buy a few extra IP adresses for it to work.

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Or use a proxy between the router and servers. No need for additional address. – John Gardeniers Sep 17 '12 at 20:45

It's not possible to forward the same port to different host based on the FQDN of a request. DNS lives in the application layer, while port forwarding takes place in the transport layer. See the TCP/IP layer model.

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