h323 & nat

["pengjie" <bill.peng@ocamar.com>]

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i had read many documents but i didn't find answer.

i have a network as following:

        A------------------B====================C
192.168.110.x  192.168.110.y  202.101.k.m     202.101.k.n

the B is a gateway doing NAT. it's eth0 is 192.168.110.y and eth1 is 202.101.k.m. there is RH9 running on it,it's kernel is 2.4.21. i have pathched the h323,and runned up the modules ip_conntrack_h323 and ip_nat_h323.

the A and the C are netmeeting clients.

i test it with 2 methods:

1)both A and C logon to a ILS.

RESULTS:
A calls C is ok, and they can chat to each other.

C calls A is failure, i see the address called is the private address of A. so setting up is failure.


QUESTION: doesn't the patch do something when client logon to a ILS?

2)call each other without the ILS.

i add a rule: iptables -t nat -A PREROUTING -i eth1 -p tcp -m multiport --dports 1503,1720 -j DNAT --to-destination 192.168.110.x

they call each other with IP address. A calls C with C's IP as the destination, and C calls A with gateway's valid IP as the destination.

RESULTS:
A calls C is ok, and they can chat to each other.
C calls A is ok, but they can't chat to each other.

QUESTION: is the rule right? h.323 streaming port is dynamic, does it result this symptom?
          even though i add the rule right,i think it's no use.it just enable one client to go through the gateway.is it?

any help is appreciated.

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