SIP client from outside the firewall?

Hello,

I have tested that Windows Messenger 5.1 can be used as a SIP client to Asterisk. However, for this to work externally, I first had to VPN into our network. I am wondering which ports I must open if I have to make this work without VPNing into the network.

Thank you in advance for your help.

Pradeep

Depends on in which directions you are talking about. Generally it is the port in your /etc/asterisk/sip.conf (default 5060) and ports in /etc/asterisk/rtp.conf (generally a range, something like 20000-20100). Also, have a look here for more details:

voip-info.org/wiki/view/Asterisk+sip+nat