We have installed a voip system from Interactive Intelligence (Indianapolis Oh). We get dial tone from two sip trunks for inbound and outbound calls. Works great. Between sip router, and server, is a firewall. Firewall does not play nice with t38 faxing. Anyone have a similar setup that is working for t38 fax?

NOTE:  scary...but fax work fine if firewall is removed.  Fortigate support is working on this as well, but I'm not getting a good vibe.

So, I'm willing to change vendors on the firewall, if I can find one.