NAT help needed for Windows 2003 server

[dtrobert]

Hi,
I am trying to setup NAT on a Windows 2003 server. I don't need or care if other systems use it to NAT, I only care about requests emanating from this server itself. I need to NAT a couple of static address, and then an entire range with a dynamic rule. For example, all 192.168.101.X -> 172.17.18.X where the X's match.

I have started the Routing and Remote Access UI, and added under NAT/Basic Firewall my Local Area Connection. There's also a default route that will carry all traffic working (tracert).

In this NAT entry, I set:
-Public interface connected to the Internet = true
> Enable NAT on this interface = true

Then on the Address Pool tab, I added the 2 IP ranges I wish to NAT. Under Reservations I added the static IP mappings I wanted.

so....
1) I try to ping the external IP and it's not going anywhere
2) I don't see how to configure a dynamic nat at all

Any help is greatly appreciated.

 

[lhuegele]

Sounds to me like you may have a router that needs to be re-configured to see your new NAT'ed address space, or you have vlans that you need to consider and fix.

Good luck

 

[dtrobert]

Well, the router (NAT device) knows how to route packets for 192.168.101.X fine. I want the packets leaving the Windows box to be sent towards a 192.168.101.X address but for the application running on the Windows box to just send them to the 172.17.18.X address. The router should be entirely unaware anything is happening on the Windows box.

 

[lhuegele]

In 1) above you stated that pinging the external IP address doesn't go anywhere. Are you pinging it from outside your network or inside?

I've seen routers and firewalls block access to the external interface from within the network.

Also, just FYI - I would never set up NAT on a server. I have always done it at the perimiter (i.e. the firewall) level.

Good luck,

 

[dtrobert]

I am pinging from within the Windows box itself. There is a specific reason I need it to run on this server. The application on the server only works with internal IPs. It puts the IP inside the packet itself (not header). So I am trying to trick it into thinking there is no NAT.

 

[lhuegele]

I would try your pinging from outside your network, assuming that your firewall is set to allow ping responses.

Good luck,

 

[lhuegele]

You might also want to check your firewall logs for any information that might help you track down where the problem actually is.

Good luck