Has anyone seen an issue where the RTP ports change on the phone back to the PBX? I have an Ephone3v2 going back to a 50x eSIP system. It will dial etc, but no voice. Doing a package capture, it shows SRC as port 10004 but DESC is 22604. We done a factory reset and it still changes the DEST port atleast 10k higher than the RTP ports. The 10000 to 12000 ports are forwarded on the FW to the PBX. We added the 21000 to 25000 range as well but still does not work.
It might be your firewall that's changing the RTP assignments. Sonicwall's are particularly prone to this. There are settings that will disable this, but for the life of me, I can't remember what they're called.
We do a have SW and I disabled SIP ALG. I tested from a home internet connection and the packet trace shows the port change as well. In the IPPhone settings, it has port range 10000 with increase 1000 max ports.
Enabled the source port. Same result. I reached out to ESI for some help. Even tried another brand new IP phone and getting the same result.