Fax received successfully, but the call dropped prematurely

Hello all.

I’m running Asterisk 1.8.5.0 with res_fax_spandsp. Spandsp is the latest snapshot (20110703). I’m working on receiving faxes and am consistently getting “The call dropped prematurely” for a specific number. Despite this error, the TIF file is received correctly and the sending side declares the transmission a success. I’m confused as to why Asterisk thinks this is a failed call.

The Asterisk machine is running behind a firewall, but all ports have been forwarded for debugging purposes. Additionally, externaddr and localnet have been set. The box is running Ubuntu 11.04 amd64.

Attach you’ll find my sip.conf, extensions.conf, log file from the call, and a packet capture.

This one is really stumping me.

Thanks,
Josh

Messages.log: pastebin.com/saHijDse
Sip.conf: pastebin.com/BNuHPZqx
Extensions.conf: pastebin.com/ggYBawut