Far End NAT Traversal (FENT)

The Internet Gate can enable SIP connectivity for remote users that use NAT devices without SIP support. It can adapt to characteristics of remote NAT devices.

You might need to purchase a license to be able to use FENT in your unit.

FENT sends keep-alive packets to remote SIP clients behind non-SIP-capable firewalls to keep the SIP communications channel free to them.