I am using pfsense 2.2.6-RELEASE. My configuration is as follows:
- Two static WAN, One LAN
- Using google and opendns
- Configured WAN-Load balancing and WAN-Fail-over
- Using aliases in firewall rules
When the primary WAN interface goes down, the DNS stops working.
There is fix available on pf-sense forum, but the forum is closed. The link for forum posts is here https://forum.pfsense.org/index.php?topic=43982.0