IP Aliases cannot be used for routes/gateways
Version: 2.0.3-PRERELEASE, 2.1-BETA1 (Apr 18 2013).
Short: The system will not allow a gateway to be created where the IP is within a subnet used by an IP alias -- only the main/primary IP subnet of an interface can be used.
Two pfsense firewalls. FWA and FWB. Three IPv4 subnets. 192.168.0.0/24, 192.168.1.0/24, 192.168.2.0/24. Assigned as:
FWA: 192.168.0.1 (LAN), 192.168.2.1 (LAN IP Alias)
FWB: 192.168.1.1 (LAN), 192.168.2.2 (LAN IP Alias)
Attempting to define a gateway of 192.168.2.2 in "System -> Routing -> Gateways" on FWA fails with the message that 192.168.2.2 is not within the LAN interface subnet, 192.168.0.1.
Should "just work" with no error message. Works as expected on all normal routing hardware, as well as on standard *BSD installations via "route add ..."