I'll be shocked if anyone can help me with this, but I've been working on it for over a month and am no closer to a solution now then when I started!
Here's the deal: we have a MITEL 3300 PBX that we use for VoIP communication at our company. We've been experimenting with Softphones, specifically with Counterpath's Bria 3, and have had great success inside the network. Outside, however, has been a different story. I put NAT rules/ACLs in place to allow inbound traffic to be routed to/from our MITEL PBX, and at first it seemed like it would work great (first connection from the outside did just fine). Later, however,we found most people couldn't connect from their homes/hotels/etc.
More research turned up that some routers have built in SIP Application Layer Gateways, which rewrite the SIP packets in some magical way that allows them to connect. Every router we've used that doesn't have a built-in ALG fails. After comarping Ethereal packet traces, I've determined that the only difference between a succesful connection and a failed one is that succesful SIP packets do not contain the 'received=outside IP' parameter in the Via header while failed packets do.
What can I do, either in Bria, my Cisco ASA, or to my MITEL 3300 ICP that will allow this blasted softphone to connect from regular routers? Is this software just doomed to fail unless I'm passing through a special ALG enabled router?
Before anyone suggests: Yes, I have tried using stun.counterpath.com. It doesn't work.
Thanks in advance!!