Firstly a few things:
One, make a dmz whit the fileserver and mailserver
You can not have 2 DMZ targets
Two, use two uplink interface for a failover
Failover in the current Community version can not switch back and forth.
ie: If Red(a) fails, system will switch to Red(b) - but then if Red(b) fails system will not switch to Red(a) again.
Perhaps this will be fixed in the next version.
Mail Problem.
You can use the SMTP proxy or you can set it up manually like this:
Access from
ANYTarget
<ANY Uplink>Filter policy
AllowService/Port
SMTP Protocol *
TCP Target port/range
25Translate to *
IP DNAT Policy
NATInsert IP
192.168.1.200 Port/Range
25The port for receiving mail is 25, not 110 which is the POP3 port.