One you start to pile more and more vm's, you realize something is "oh no" quickly when you only have one static IP address from the isp.
The problem is that you have vm's that are all grabbing the same ports.
Gone the days when a web server only needed port 80, or the email server that only needed port 25.
Consider: a vm of MS Exchange, a vm of a Citrix something, and an ubuntu with god knows all sorts of goodies on it, yet all three vm's are fighting for the same ports.
You can only NAT (network address translate) so much, in the end some ports simply can't be dedicated to one vm and not the others.
Most hardware routers can't do any sort of reverse NAT or reverse proxy.
domain.com and www.domain.com -> vm at 192.168.0.10
exchange.domain.com -> vm at 192.168.0.20
citrix.domain.com -> vm at 192.168.0.30
dontmakemeuseasp.domain.com -> vm at 192.168.0.40
anyhost.domain.com -> vm at 192.168.0.nnn
A visitor from the internet will always resolve the same one public IP from a dns lookup of something.domain.com, so the router inside the LAN must port forward to the right vm accordingly.
I am told that software appliance routers (like a vm of pfsense) can do reverse proxy, but that means I have to stop using my trusty sonicwall hardware router that has been faithful over the years.
I'd just like to know some ideas that vm lovers here have gone about this?