@phil.davis:
For your web and mail servers, did you set the default gateway xx.xx.xx.25 (the cable modem)? I am fairly sure the pfSense box is supposed to be invisible to the servers.
IMHO the servers in the DMZ have to have the pfSense DMZ IP as their gateway. That is the only way out for them from their subnet to the rest of the world.
In this kind of situation, the pfSense is being a "normal" internet router. The internet (ISP) is routing packets for the allocated DMZ public IP subnet to the pfSense, and expecting it to route them to the destination. The pfSense role here is to route the packets, and to front-end filter incoming stuff, so the servers in the DMZ only get necessary open ports accessed/attacked. There is no point letting everything through to the DMZ servers - they would appreciate a bit of protection from random scans/attacks on other ports.
ok - but from this point of view (which is also my own one) an fully 1:1 bridging is not apreciated.
The role pfSense does NOT have to perform is NAT/port-forwarding, as the DMZ already has real public IP addresses.
yes, but exactly this is my problem – 1:1 bridging which i have tested as a hopefully working approach does not work and i do not know what to do to tell the WAN interface to accept public DMZ IP's