Net research NetProbe 2000 User Manual page 305

Direct connection to the internet – use this option for making calls in local network or using proxy to route your calls. If
you find yourself in a private network behind a NAT/firewall and if you do not use SIP provider to route your calls, you
may need to use one of the following NAT traversal options.
Behind NAT/Firewall(specify gateway IP) – specify manually the IP address of your NAT router in Public IP address entry
area.
Behind NAT/Firewall(use to STUN to resolve) – use STUN server as an intermediary to resolve the public IP of your NAT
router. Enter the IP address of the STUN server in STUN server entry area.
Behind NAT/Firewall(use to ICE) – use ICE protocol. Enter the IP address of the STUN server in STUN server entry area.
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