What a load of packets! - SIP / EXTERNAL IP

Hello, I’m Russ and I’m new here.

I can find zero info on this, and I have searched hard!! So don’t kill me if this is basic.

I have two sites connected by a VPN.

I have a feeling that Asterisk is treating the remote site extensions as external devices beacause they register with an IP from a different range [even though I have NAT turned off for the extensions]. Therefore Asterisk uses the external public ip address of the Asterisk server in the INVITE or whatever to these devices.

The voice traffic is then sent over the public internet and not over the VPN. As a consequence, my firewall drops the voice packets. (For some reason SIP works fine, the call sets up, BLF NOTIFY works still etc)

The only way I could get the remote phones to work properly was to set the exernalip of Asterisk to it’s LAN address as a workaround. Luckily the VoIP trunk to my VSP still works, I think the SIP ALG on the router is to thank for this.

Question is: Is there any way to define your various remote site subnets so that Asterisk doesn’t substitute the LAN address with the public IP? i.e. so devices connected by VPN, although on different ranges, are treated as local devices?

(I have elected not to upload my config files as I don’t think they are relevant to the question, and they are not pretty :frowning: )

Did you define the iprange of the site as a localnet in the sip.conf ?


You legend Ian,
I hadn’t, so I just added it, changed back the externalip and it works great! :smile:


Good, Just to clarify fo any one else, you should always define the external ip address and then define the localnet for ALL subnets that phones are on.