Hello I'm kind of new to networking and I'm having a small problem of.. not knowing where to start.

I have three Windows2012 servers which I would like to assign three IP's from my range given by Frontier.

My network goes as follow, ATT Rack -> Small Business Cisco Router RV042G -> SonicWall NSA 2400 (Passthrough, L2-Bridge) -> Switches -> Server A (DNS, DHCP, AD DS, DC), Server B (IIS,FTP), Server C (IIS,FTP).

My ideal set up would be to have, x.x.x.178 ServerA (RDP Only) x.x.x.179 ServerB (HTTP,FTP) x.x.x.180 ServerC (HTTP,FTP)

A consultant CCNA told me it was not possible with the current hardware, he said I would need something capable of proper NAT routing. So this is where I am stuck.

At the moment I am only using x.x.x.178. HTTP is port-forwarded to ServerB, while RDP is forwarded to ServerA. This was done through the Cisco Router Web Interface, and the sonicwall is passing through all traffic for now.

I'm completely new to networking and I would appreciate any pointers in the right direction.

  • Are you sure the the Sonicwall is in L2 bridge mode? And if so, what is the point?
    – cpt_fink
    Commented Feb 20, 2015 at 8:07

1 Answer 1


Unless I'm mistaken, the RV042G can do 1 to 1 NAT. There's a guide on Cisco's website on how to enable it here.

In general, lets say your public IP block includes through .180 as usable IPs. And your LAN is 192.168.1.x. You'd make 1 to 1 NAT mappings so that maps to, to, etc, with .177 used for the rest of your network.

Also, you only really need to do multiple public IPs if you are hosting services on the same port. Since only Server A is doing RDP, you don't need to give it's own public IP and it can share .177 with the rest of the network, with the appropriate NAT and firewall rules for the RDP port. .

  • Thanks! This seems exactly like what I need but unfortunately it seems like this router cannot map to a subnet. I skipped through some other forum posts and from my understanding, its not a feature available on this router... though I may be mistaken.
    – MrGoodGuy
    Commented Feb 20, 2015 at 18:04
  • Just to make sure I'm on the right page, can you explain a bit more about the problem you are running into? Is your LAN on multiple subnets? For example, are your workstations on 192.168.1.x and your servers on 192.168.2.x?
    – pooter03
    Commented Feb 20, 2015 at 19:44
  • What do you mean with "map to a subnet"? The exact purpose of a router is routing to a subnet - if it can't do this it's not a router. However that's only possible if the router has an IP interface in that subnet. So your router must have an IP address X.X.X.Y. Commented Feb 21, 2015 at 12:55
  • the router is on, while the lan is on 1.0.1.x, wlan on 1.0.2.x. the servers are on dhcp, dns, ad is handled by server A. whenever I try to 1:1 NAT on the router, I get an error saying "this ip is not on the same subnet".
    – MrGoodGuy
    Commented Feb 24, 2015 at 20:15
  • I was sorta able to achieve this by literally adding a secondary IP on 10.0.0.x to each server, and 1:1NAT to that secondary IP. But now DHCP is stopped working. However, If I manually add the information on client computers, they get internet just fine and are able to join the domain.
    – MrGoodGuy
    Commented Feb 24, 2015 at 20:21

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