2 web servers from 1 public IP address (IIS)

[dmad]

I've heard this is reasonably simple - but does anyone know how to host 2 web servers from behind one public IP address?

For business continuity, I have setup two Windows Servers - one hosts some web pages and OWA and the other is hosting Kayako. However I only have 1 static public IP and its becoming a real nightmare to aquire additionals (in the short term).

One thing that was suggested was changing the port of the web traffic on the IIS server and then telling the main router to forward traffic into that port across to the 2nd IIS server. Not sure how i would go about this though - any ideas!?

[craigbrass]

Only way would be to put them on separate ports on the IP.

[gbrown100]

You have a couple of options:

1: If your router does port translation you can forward for example as below:

PUBLIC IP:80 forward to Server1:80
PUBLIC IP:81 forward to Server2:80

Some routers do not do port translation only port forwarding - port forwarding is where the port on the public IP can only be forwarded to the same port on the internal IP (NetGear DG834G does this) - Port translation allows a different port to be assigned to the internal IP (hence translation)

2. Use a reverse proxy server. You should be able to use a reverse proxy server which intercepts the traffic and forwards it on to the correct server. I have done something similar with Apache and the ModRewrite function before. It would work something like this:

www.domainname.com/server1 - forward to 192.168.0.1:80
www.domainname.com/server2 - forward to 192.168.0.2:80

This is done transparently so the host will only ever see the domain name not where to content is served from.

[StevenCTP]

You should also be able to create some cool rules using NLB and host-headers (assuming that each of the services is a different host-header) such that both machines really would "share" the one public IP - using Microsoft's NLB, but would behaive somewhat differently thanks to some creative IIS configuration.

[John Haugeland]

There are a million ways to do this. The most common approaches are to use a single web server taught to act like two seperate servers, such as through Apache's NamedVirtualHost mechanism, or to run two distinct servers on separate ports.

I think you may find NamedVirtualHost to be far more convenient than running entirely distinct servers; the outside world can't tell the difference.