I've got a SonicWall TZ210 which connects to the WAN via PPPoE on the X1 interface. I've got a /29 subnet routed into the box, and everything is running fine.

Now, I need to route one of the WAN IP addresses directly to an internal machine without any NAT being performed on the firewall.

I've set up a test network in which I assign an interface as part of the DMZ zone and set the interface to Transparent IP Mode, set the WAN IP up on a test Ubunutu box connected to that interface, and everything is running fine.

However, when I come to replicate this on the live TZ210, which has PPPoE on the WAN interface, it gives me an error Error: Index of the interface.: Bridged-to interface must have static IP assignment, meaning this configuration won't work because of PPPoE.

What's the best route forwards with this?

  • I'm curious, why can't you run NAT? Apr 23, 2014 at 17:40
  • It's for a MS Lync server, and NAT is buggering up the SIP traffic. Apr 23, 2014 at 17:41
  • I am not sure your requested pppoe config is supposed to work. Generally something like a session border controller is used to make NAT work with Lync in this scenario; I am not sure sonicwall has SBC functionality Apr 23, 2014 at 18:16
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    Nov 19, 2022 at 21:38

2 Answers 2


Easiest solution? put a router in the WAN, without NAT, and you'll use your L2B mode.

You'll lose one IP (Router LAN/WAN) but it'll give give you a static interface and clean config!


If you want to put a device in the DMZ you will need to assign another physical interface to the DMZ. The error is telling you the DMZ interface needs a static IP.

If all the hosts behind the firewall are public visible (public IPs) then you just need to setup firewall rules. Otherwise you will need to build a DMZ where you static assign some IPs. Also note the host must be added as a host with a static entry.

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