NAT and UDP ports

[g4swx]

After 2 years of great remote operation (including exhibition stations) I have decided to upgrade my station to allow me to control several radio RRCs. I have a linked private IP network and obviously I can choose the ports and IP addresses to be whatever I want. I have chosen the same port numbers for command/SIP/Audio on all radio RRCs. To change a control RRC from one radio to another I simply change the profile to another radio RRC destination IP address and all works fine.
However, there is only one external Internet IP address and I wanted to be able to address more than one radio RRC over the Internet.

What I tried and so far failed to get running is to NAT (13000 to 13001 etc) the three UDP streams from one of the radio RRCs at my firewall (Cisco 1801). I then changed to control RRC to match the same external port numbers. This would be nice as I could keep the inside network the same but address multiple radios over the Internet by simply changing the ports from profile to profile.

Looking at the status of the control and radio RRC after attempting a connection shows differing in/out ports for command/SIP/Audio so I presume that the communications protocol will not accept UDP NAT. Is this correct?

I realise that if this is the case I will have to change the ports so that each radio RRC has a different set and then simply open the relative UDP ports on the firewall. Any other thoughts on how to configure the network gateway for multiple radio RRCs?


73
John G4SWX

[dj0qn]

Hi John,

Sorry, you must issue completely different ports for each RRC and forward them separately in the router
specifically to the correct internal IP number. You then always use the same external IP number or
Dynmic DNS address for all RRC's, but the different ports will send you to the correct RRC.

73,
Mitch DJ0QN / K7DX

[g4swx]

Hi Mitch,

I should have guessed that because the protocol incorporates SIP you cannot NAT the UDP ports in the middle.
As I now have 3 radio RRCs running changeover is becoming complicated...

73
John G4SWX