Bad Acknowledgement Packet

I did a fresh CentOS 5.8 install on a brand new HP box and installed Asterisk right on top and then FreePBX on top of that to mimic AsteriskNOW. I didn’t use AsteriskNOW because I was having issues with the ISO (another story). Anyway, EVERYTHING about it works fine except outbound calls. Outbound calls drop anywhere from 15 seconds to 10 minutes. Somewhere between that time range the call will just drop. I troubleshooted with out SIP provider and they said that their server asks our server “Is the call still going?” every now and then and our server is supposed to respond with an acknowledgement packet saying “yes, yes it is” but that packet is being sent incorrectly/improperly formatted and so their server never really sees what it’s supposed to and just ends the call.

The server sits behind a SonicWALL firewall with a 1:1 NAT (yes, consistent NAT is enabled on the SonicWALL) and all necessary ports opened to the outside. The Polycom phones we use (primarily SP321s) connect to it directly via LAN (there’s no local firewall up on the server. The version of Asterisk we’re using (by typing “asterisk -V” is 10.5.0 and we’re on CentOS 5.8. The FreePBX version shouldn’t matter but I don’t know how to find that version anyway. If you need it please let me know how to find it.

Everything about it works beautifully. The ONLY problem is outbound calls because of the bad packet being sent from our server. Inbound and pretty much every other feature works flawlessly. Thanks for your help.

You need to provide copies of the request and response packets (they are all text). You can get them using set sip debug on. Also you need to get the ITSP to identify the exact defect.

My initial guess is that the NAT device is not natting the packet properly.