[AdamAtCamiant]

Folks -

I'm trying to test Sipura adapters for use in broadband-based VoIP networks (no suprise there). The Sipura adapters are behind a home-gateway style NAT device to simulate a user home location - the inside NAT addresses are 192.168.X.Y. Outside of the NAT is my company's network, also private - 10.0.0.Z. I'm using STUN for NAT address correction - the STUN server is set up on the 10.0.0.Z network.

Oddly, the Sipura doesn't seem to want to use a 10-net address, even though I see the request come into the STUN server and the STUN response return indicating the 10-net outside address. Neither the VIA nor the Contact fields in the Sipura's REGISTER to the SIP server (also on 10-net) have the external address in them. If I place the Sipura on the 10-net and go through our company NAT to the Internet, e.g. stun01.sipphone.com, it corrects it's external address.

Is this some funny public/private address thing that anyone knows about? Anyone else had trouble getting Sipura to accept a private address as the external address for substitution? I've set the stun server IP, enabled STUN, and enabled VIA substitution . . . is there anything else obvious I could have missed in the configuration?


Thanks,
Adam

[Kir]

I do not see anything wrong with the situation you described. Sipura correctly identified a private IP and declined to accept it as its external IP.
Private IPs are, by strict rules, non-routable.

[PhoneBoy]

RFC-1918 defines the following private address space:

10.x.x.x
172.16-31.x.x
192.168.x.x

Anything in this address space is considered private and non-routable. Since the entire purpose of STUN is to eliminate private addresses from SIP packets, it makes sense to ignore any RFC-1918 address it obtains from the STUN process.

[pap2boy]

Originally Posted by AdamAtCamiant

Oddly, the Sipura doesn't seem to want to use a 10-net address, even though I see the request come into the STUN server and the STUN response return indicating the 10-net outside address. Neither the VIA nor the Contact fields in the Sipura's REGISTER to the SIP server (also on 10-net) have the external address in them. If I place the Sipura on the 10-net and go through our company NAT to the Internet, e.g. stun01.sipphone.com, it corrects it's external address.

This isn't an odd thing. You get what you ask for. FYI, STUN server option will only work on a non-symmetrical NAT/Firewall router. Chances are your corporate uses a symmetrical NAT/Firewall router. So, your statement on Sipura regarding the use of 10.x.y/24 net is a complete false statement. Please read the Networking section on FWD FAQ to learn about STUN/NAT.

Good luck.