Appendix E: Special note about extensions over VPN

In order to make extensions work over VPN’s we had to add the VPN subnets to sip_nat.conf to make the phones on the 192.168.2.0 and 192.168.3.0 subnets work with the Asterisk Server on the 192.168.1.0 subnet.  Here is the whole sip_nat.conf file

nat=yes 
externip=xxx.xxx.xxx.xxx 
localnet=192.168.1.0/255.255.255.0 
localnet=192.168.2.0/255.255.255.0 # VPN1 to 192.168.1.0 
localnet=192.168.3.0/255.255.255.0 # VPN2 to 192.168.1.0
externrefresh=10