I thought I’d post this in case anyone here has run into a similar situation and may have a clue. This is definitely a pfSense related issue.
Scenario:
RentPBX hosted FreePBX server is not receiving TFTP requests from phones located behind a pfSense firewall.
Another office is using a Cisco ASA, and has no problem getting requests sent to the server.
pfSense version 2.1.3-i386
Outbound rule to allow all traffic from LAN
Inbound rule allowing all traffic from RentPBX server
TFTP helper enabled on both LAN and WAN (have tried all combinations)