Asterisk under NAT

If your Asterisk box is under NAT, you should edit /etc/asterisk/sip.conf file:

[general]

externip = <YOUR REAL IP>
localnet = <LOCAL NET IP/MASK>

Example:

[general]

externip = 23.45.67.89
localnet = 10.10.1.0/255.255.255.0

Forward SIP ports (UDP 5060, 10000-20000) on your firewall to this Asterisk machine.

Restart Asterisk.

[edit] Attention!

Do not put these settings in wrong place! They should be in [general] section.