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I have two separate web servers with two different internal IP addresses on a network with only one public IP address. One is Windows Small Business Server 2011 and the other is a new e-mail encryption gateway appliance.

I have subdomains configured for and both pointing to the same public IP. I need both of these subdomains to point to the correct internal server both on port 80.

I've configured forward lookup zones on the SBS server pointing to the appropriate IP addresses. I have a SonicWall NSA 220 firewall. I had firewall rules to redirect 80 to the SBS server, but I've set up an overriding rule to redirect 80 to the gateway appliance until I can get both services operating concurrently.

I referenced this thread, but my situation is different enough that the responses to it don't apply.

Thanks in advance!

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up vote 0 down vote accepted

The solution in the end was to host the e-mail gateway appliance's web server on a different port. This is not ideal, but, since most of the end users who would access it will do so via clicking a link in an e-mail, it's sufficient.

No form of redirect will work with two separate internal servers and only one external IP.

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You could have the external IP go to a proxy that determines the proper backend server to talk to via the Host: header. The name for this (and what you should search for if you want more info) is Reverse proxy. – yoonix Aug 13 '13 at 20:00
Thanks, yoonix, you're right. I did some research on reverse proxy and determined that it would not work in my case (though it was a few months ago, I don't recall now exactly why it wouldn't have worked). Of course, this was my own unguided research into a field I am not familiar with. Had I gotten a response earlier from someone more experienced in web hosting I may have found it to be the solution I needed. – Thomas Aug 13 '13 at 20:28

I've done this with pfSense and the Mod_Security+Apache service with no problems for quite some time now. There is something like 15 VMs all running various web servers / web based consoles for software appliances, all on ports 80 or 443 with everything behind 1 public IP.

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Oh, Kitt, I sure wish you had been here 6 months ago! I have to ask... Knight Industries Two-Thousand? – Thomas Aug 16 '13 at 5:21
You bet :D ... and it's been my nickname since grade school, which is ironic because now I am big into AI and automation. – Kitt Aug 16 '13 at 12:21

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