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I am looking to setup CARP following this guide across two pfSense firewalls.

I have setup CARP before on a WAN link with a big IP space, so allocating a distinct WAN IP per each device (as shown in the guide) was palatable.

Now, I am trying to do the same, but only one WAN IP is available per link.

Is there a way to use only one WAN IP?

Edit: What if you have the following configuration? (would this work?)

  • WAN1: WAN IP, local IP
  • WAN2: WAN IP, local IP
  • pf1: On interface WAN1, local IP; on WAN 2, local IP;
  • pf2: On interface WAN1, local IP; on WAN 2, local IP;
  • On both pf1 and pf2, monitor IP set to the ISP-appropriate value
  • VIP on,
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2 Answers 2

up vote 6 down vote accepted

No, carp requires three WAN IPs.

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CARP is like VRRP, HSRP and most other routing redundancy protocols, you must have 3 static IPs in the same subnet.

That may change at some point in the future, but it's true for the time being.

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