@@Here is the description of the problem.

I have Asterisk setup at a collocation site.
When I place a call through this box - one side of the conversation can not hear the other 
person, while the other side hears everything just fine.

@@Behavior Clues:
Every once in a while (Rare) both sides can communicate fine for a couple seconds, then one 
side slips back into problem described above.
If both callers use Meetme they can communicate fine with no problems.
I have another box with the exact same configuration (dev box) at a local location and it works fine.
This problem happens regardless of the type of device (although a sip connection is always in the 
loop) - I have used softphones, 2 types of ATA's, and when calling on regular phone through provider.
Problem exist whether I send the call through my provider or route the call between two extensions local to my box.


@@Things I have tried:
I have turned off the local firewall on the box (iptables).

When I turn on rtp debug I get the following when I dial from one of my extensions to a phone not on my network (cell phone):

Sent RTP packet to <provider ip>:10006 (type 18, seq 50928, ts 24040, len 20)
Got RTP packet from <provider ip>:10006 (type 18, seq 50000, ts 74645, len 20)
Sent RTP packet to <ATA IP>:16468 (type 0, seq 50088, ts 24560, len 160)
Got RTP packet from <provider ip>:10006 (type 18, seq 50001, ts 74805, len 20)
Sent RTP packet to <ATA IP>:16468 (type 0, seq 50089, ts 24720, len 160)
Got RTP packet from <ATA IP>:16468 (type 0, seq 9434, ts 169235320, len 240)

When I turn on rtp debug I get the following when I dial from a phone not on my network (cell phone) to one of my extensions:

Nothing


When I turn on rtp debug I get the following when I dial from one of my extensions (softphone) to one of my extensions (ATA):

Got RTP packet from <NAT RTR IP>:2978 (type 3, seq 1, ts 74560, len 33)
Sent RTP packet to 192.168.0.2:16472 (type 0, seq 35725, ts 0, len 160)
Got RTP packet from <NAT RTR IP>:2978 (type 3, seq 2, ts 74720, len 33)
Sent RTP packet to 192.168.0.2:16472 (type 0, seq 35726, ts 160, len 160)
Got RTP packet from <NAT RTR IP>:2978 (type 3, seq 3, ts 74880, len 33)
Sent RTP packet to 192.168.0.2:16472 (type 0, seq 35727, ts 320, len 160)