Question : SMTP problems with SMC Barricade soho firewall (SMC7004VBR)

SMTP problems with SMC Barricade soho firewall (SMC7004VBR) - I've got a strange problem with an SMC Barricade.  I have a small office with three PCs behind an SMC7004VBR (751.7922) (hardware v 1.01, boot code: r1.0606.0707) which is behind a new Actiontec/Verizon DSL modem.  

Recently I replaced the DSL modem.  The next day I began having trouble with SMTP traffic on all three workstations.   Outbound mail was not being delivered.  However, when I plug my laptop (not one of the three PCs on site) into the SMC SMTP traffic is delivered.  I spoke to SMC L1 techs who implied that this may be an issue with the SMC7004VBR and we tried port triggering for 25/110 to no avail.   I know of no reason for the SMC to interfere with SMTP and a review of the interface reveals no outbound filters.  Next step is to replace the SMC with another device.  Anyone have any suggestions?

Answer : SMTP problems with SMC Barricade soho firewall (SMC7004VBR)

Is the Actiontec a combined modem and router? if so have you tied by-passing the SMC just a s a test? If it is a combo unit you may want to put it in bridge mode to simplify the connection. Bridging effective makes the Actiontec a basic modem.
You shouldn't need to use any port forwarding or triggering as this is an outgoing connection.
It is possible that if the Actiontec is a combo unit, that it uses the same LAN side subnet as the SMC causing some routing issues. Putting the Actiontec in bridge mode would eliminate that.

I assume changing the modem does not mean you have changed ISP's?