[Asterisk-Users] IAXy Port number

[Chadwick E. Labno]

The file used with a Digium IAXy device: "iax.conf"
has the line: "port=5036" (I also use the "bindaddr=192.168.1.91" entry)
but when Asterisk talks to the IAXy device it
used port 4569 (from "tcpdump"). How are the port numbers assigned?
What tells the IAXy which port to use. The IAXy provisioning file
"iaxy.conf" file does not specify a port (I'm configured for static IP).
I'm trying to use the IAXy device across a VPN.