1to1 NAT with multiple WAN gateways

I like to configure a 1to1 NAT for our 3CX SIP telephone appliance.

I've to define a lokal IP to one external IP.

Our WAN:

WAN1 :
WAN2 :

In the multi WAN config WAN2 is prioritized and the settings on failover

Internal IP:

I tried to define the 1to1 NAT like this:
Interface Of Hosts NAT Base Real Base

But the defined host got still a IP from WAN2

I guess it is the multi WAN setting failover? Should I change it to Routing Table?


  • Options

    What XTM version are you running?

    What is your goal for WAN1? Only use it for backup use?
    If so, look at using SD-WAN (or Policy Based Routing) instead of using Multi-WAN Failover.
    Consider using Multi-WAN option Interface Overflow

  • Options


    we're running an Firebox M200 with actualfirmware build 12.2.1 (yes, i know there are newer ones,...

    First our goal was to 've a redundance with the slower line. But for now we want to use it simultanous

  • Options

    Consider using Multi-WAN option Interface Overflow, that way you still get to use the 2nd WAN interface, but only when there is more traffic than the 1st WAN interface can handle, and doing so will not automatically compete with your VoIP traffic which will be on WAN 1.

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