Bypassing Policy Routing

PF's route-to functionality, employed by pfSense's multi-WAN capabilities, will force all traffic matching a firewall rule specifying a gateway out to the specified gateway. Negation rules are automatically added for VPN subnets, but where other internal subnets are on the firewall, or you need to access a pfSense interface IP (for services such as DNS) you need to add a rule specifying the default gateway for traffic to be routed appropriately to these networks.

An example:

In Firewall > Rules, on the LAN Tab, create this as the topmost rule, or at least above all other load balancing rules:

Proto: *
Source: *
Port: *
Destination: 192.168.1.0/24  (LAN Subnet)
Port: *
Gateway: *

The destination could also be an Alias containing all local networks, if there are more.

Originally from John Grange (JohnAtNetS) on IRC