[SIPForum-discussion] Problem with fax communication

[Ayyanar PK]

Hi,I have a problem with the fax communication.The problem is that, an outgoing fax call is made from our gateway which has a fax machine connected to it. Please find the topology belowMy GatewayRemote Gateway INVITE><  ACK  The signalling seems to be OK between the two gateways , but the T.30/T.38 messages sent by Remote gaetway never reaches My Gateway. My gateway is behind a NAT router. T38/T30 start sequence is chained correctly by the remote GW which sends DIS signal in return. However, because My Gateway has resquested port #XXXX for T38 but this port is not open on the NAT router, the DIS signal never reaches My Gateway.Consequently, the T38/T30 dialog fails and the fax call is released without success.I tried to send 'nosignal' packets just after receiving INVITE (T38), so that the port #XXXX would be unblocked and the T30/T.38 messages sent by remote gateway is routed to OXO. Can somebody help me on what can I do further to resolve the problem.Regards,AyyanarDear dis
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