Changing Internal networks or adding another internal network in Elastix, Trixbox, or FreePBX

Recently on one of the Elastix PBXs I host, I had to put up another internal network. Basically two sites were VPNed together so on the other end of the VPN were the new phones were there was another internal network. When someone would call out they could hear me but I could not hear them. This was caused by the sip_nat.conf not having the new internal network. This can also happen if you do not have the internal network and you are using a sip provider.

You have to setup the sip_nat.conf with the External IP and the Internal Network.

externip=123.123.123.123
localnet=192.168.0.0/255.255.255.0

They have 3 different networks so they have three entries for the localnet.

Here is what we did to make it work.

localnet=192.168.0.0/255.255.255.0
localnet=172.16.0.0/255.255.0.0
localnet=192.21.10.0/255.255.255.0

Once we did this all calls worked on all three networks…