NAT with RTP

[luoqiang]

Hi,   (sorry,last mail can't be seen,so I send it twice) I am a newbie for netfilter and is planing a SIP enabled module with netfilter, but some question puzzled me.   10.10.1.2¡ª¡ª159.226.1.1¡ª¡ª159.226.1.2¡ª¡ª10.10.2.2 A------>B£¨GW:10.10.1.1)-->C(GW:10.10.2.1)-------->D A(159.226.1.1:10000) D(159.226.1.2:10000)   There are two NATs,  host A and D are in the NAT. If A have known the IP address and port of D which had been mapped(159.226.1.2:10000), can A send RTP packet to D directly? In other word,if A and D had known the others mapped address, can A communicate with D directly? Does  ip_nat_expect_register() founction  in netfilter can fulfil above goal?   Thanks