<![CDATA[Colocation, Single WAN NIC, Multiple subnets, two pfSense devices with HA]]>Excuse me if this has been asked. I searched and "came close" but no definite solution.

I have several servers behind two pfSense appliances - set up for failover.
Due to a change of IPv4 allocations I'm going from one subnet to two. On one subnet I only get 3 usable IPs, on the other I get 11.

I tried simply setting up some CARP VIPs but the system won't allow it (Sorry, we could not locate an interface with a matching subnet for xxx. Please add an IP alias in this subnet on this interface.)

What is the correct way to set this up, earning in mind that I want to have failover in place? As I understand, an "IP Alias" doesn't facilitate HA.

The diagram below should look familiar.

I tried adding a 2nd WAN to the same NIC, but I can't connect to the device any longer :( …. looks like a three-hour round trip to my colo provider

]]>https://forum.netgate.com/topic/76282/colocation-single-wan-nic-multiple-subnets-two-pfsense-devices-with-haRSS for NodeWed, 15 Apr 2026 10:51:40 GMTWed, 26 Nov 2014 20:33:13 GMT60