With Recent Changes; What Ports and Ip addresses should be open to the Pap2t Adapters

[dswartz]

weird, that makes no sense!

[christcorp]

sr98user; just to clarify in case you didn't say it correctly. There are no conflicts if 2,3,4, or 20 voip adapters are using the same port. Why? Because they can't be using the same port unless they are using the same IP address. I.e. one voip adapter 192.168.1.100 using port 10001 for RTP traffic is not using the same port as a 2nd voip adapter at 192.168.1.101 using port 10001. It may seem like they using the same port, but they aren't. A port is a window in a house. You and I may have bought the same exact windos at Home Depot; but we have DIFFERENT addresses.

The only way port conflicts could come into play would be if using the Public IP address from your ISP; and you forward a port to more than one device. I.e. Any device, server, etc... that has a web interface, usually defaults to port :80. That's why when you get into your router, you don't have to put the :80 for the port. Now; if you have a router, voip adapter, web server, etc... and they all use port :80; then forwarding from the outside world can get tricky. It can definitely be done, but that is usually where a port conflict would come in. But in the voip world, the SIP is talking to your voip adapter to ring it and such, lets say on port :5060. You can have 5 voip adapters and ALL of their sip ports can be :5060. There isn't a conflict because each adapter has a different IP address. Same with the RTP traffic. later.... mike.....

[sr98user]

christcorp,

You are correct. If two ATAs are behind your router are using port 5060, then your router maps one of the ATAs to something different than 5060 on the public side. But on the way in, if the data is sent to the correct public port, it will reach the correct ATA.

Like you said, if you are doing port forwarding, you should be aware of this. Since the OP was using the term "PAT" (port address transalation, which is what we all have and not NAT), I think the OP is familiar with what they are doing.

Also, when you use multiple ATAs, since the port numbers could be different on the public side, in many cases you probably need to enable STUN. STUN will figure out correct public IP and port and use that in the SIP messages. Sometimes the routers might change the IP/port in the SIP messages (I think that was ALG does). I think that's the reason some combination of routers/ALG/STUN don't work well.