I have RB112 + CM9 with 15dbi Omni AP mode work on 2,4Ghz installed on my network. Everything functioned well, but one day a problem occured when one of my cutomers is doing/having a video teleconference by using H.323 protocol. The problem is that my MT is oftenly automatically restarting during making a call with video teleconference.
note :
signal on AP = -60dBm
test bandwith client to MT = up to 2Mbps both direction (MT test Bandwith)
bandwith used = 384kbps full duplex
Please help me. Thanks
Yep, there is a problem with the H323 NAT helper and it kernel panic’s the OS. Mikrotik needs to fix this. In the mean time, we had to resort to passing through a public IP to the customer’s H323 device (video conferencing in our case) to avoid NAT’ing the customer traffic. This avoided the problem altogether.
We ran into this problem as well, and were told by MikroTik support that they won’t be able to fix this problem in 2.9 because of a limitation in the 2.4.x Linux kernel. We will have to wait for 3.0 for a working H.323 helper that doesn’t crash the OS. 
In the meantime, we, too, have just had to turn off the H.323 NAT helper and make sure that those who need H.323 videoconferencing have a routable address.
– Nathan