Windows DHCP Port Forwarding

Question

I am using windows 2003 server as a DHCP server and I have around 10 computers behind it. How can I portforward some ports?

Answer 1

DHCP and port forwarding are two very different things.

DHCP is for assigning an IP address, Subnet Mask, Gateway, DNS and other predefined network settings.

Port forwarding is the ability to publish (can't think of a better word) a port from an application or service from a machine running behind a firewall, router or other blocking device.

If you are however saying that you want to publish a DHCP server to another machine, you will need to forward ports 67 and 68 - however, DHCP also works through the broadcast address. This can cause a lot of problems when running through separate networks, so take a look to see if your router supports DHCP chaining, routing, forwarding or whatever your vendor calls it.

Answer 2

Most of the time, you forward a port to a specific IP, which poses problems when the IP of a machine is set dynamically (the D in DHCP stands for dynamic). Essentially, you are never guaranteed that a particular machine will have a particular IP, unless you go through a lot more rigamarole with your server, like reserving dynamic IPs for specific MAC addresses. Some software will allow you to set up port forwarding based on MAC address, which, if you want to keep all your machines on DHCP, may be the way forward.

Personally, I prefer to set static IPs for machines that need ports forwarded and reduce the range of assignable DHCP IPs so that your static IPs fall outside that range. Then you can port forward to your heart's delight.