[Serusers] natpings disappear?

[Jev]

 >>I can still make outbound calls after the udp pings stop, but I can't 
receive
 >>calls. I'm not sure if the udp pings are still being sent by ser, and 
they are
 >>getting dropped at my router.
 >
 >
 >   That's important to know. If they are sent by ser and dropped by the
 >   NAT then it is possible that your NAT requires two-way traffic to keep
 >   the bindings open. If they are not sent by SER then the contacts in
 >   the user location database expired because the user agent had failed
 >   to update them.

I can not state definitively at this point that the udp ping packets are 
being sent by ser and getting dropped at the NAT router, but I am pretty 
sure this is what happening. I'm currently waiting to get access to the 
nat router in question so I can verify this.

I have however had the same problem with two different brand nat routers 
(D-Link and cisco).

What re-register time are people using (Successfully and other) on their 
UAs in conjunction with rtpproxy (or even mediaproxy)?

Thanks,
-Jev