atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems Netlink and NAPT Phones

Hi All,

I have two SV8100's Netlinked together over IPSEC VPN. There are also SIP trunks registered to the secondary system. Everything works great between the Netlinked sites, and the SIP trunks, no issues there.

However, I also have two remote NAPT phones that are connecting to the primary site. The remote NAPT phones are setup dynamic style with NAT Plug and Play enabled under 15-45. The phones connect fine and are able to use the PRI lines at the primary location. However, if I try to call an extension at the secondary location from the NAPT phones, I get an error message 'Can't Send RTP Packets' and the call disconnects. If I try to use the SIP Trunks registered to the secondary system, I get the same message.

I have the ports setup under 84-26 for the VOIP Media Gateways set at 10020-10083 for the primary system. And 20020-20083 for the secondary system. On the VPN router at the primary location I have the 10020 ports forwarded to the VOIP gateway address at the primary location and the 20020 ports forwarded to the VOIP gateway adress at the secondary location.

Has anyone out there faced a similar scenario with NAPT phones and two Netlinked sites? I've reviewed the NAPT-Netlink cheatsheet provided by NEC and setup port forwarding on both sides as recommended. I also have a ticket in with NTAC, but they need wireshark captures to proceed, which is tricky since the locations are so far apart.

Any insights would be greatly appreciated! Many Thanks!

Ports 20020-20083 at secondary system is wrong they should be the same as the primary. The only thing different would be the IP address set in that area.

Hmm.. the IP address is definitely different. I'll try changing the 84-26 program to the sames ports on the secondary system. Is a reboot required after changing options in the 84-26 program, for changes to take effect?

I think Dans is spot on. I would reboot just to be safe.

Thanks for the suggestions. I did change the ports on the secondary system to 10020 and 10083 and rebooted the system. However, I am still getting the same results, the call will go out from the SIP trunks on the secondary system, but as soon as the other end picks up, the error "Can't send RTP packets" appears. I'm thinking it is something to do with the Routing/NAT between NAPT phone > Internet > Primary System > Secondary System and then back to the NAPT phone. The call control/SIP ports 5060-5061 shows a lot of traffic, but there is not traffic coming back on the RTP ports to the NAPT phones (3462-3463) from the 10020 ports when dialing the secondary system. Thanks for the suggestions, I hope once I have the wireshark captures, it will allow more insight into the problem. I'll post the solution if I find one.

Thanks!

Confirm ALG is disabled on the routers where the VoIP phones are located.

SIP ALG is indeed off on all routers. The routers are Fortigate, if that helps anyone out there. Thanks!