GRP2612 Registered local extensions with puplic IPs on UCM6304A


Hi , guys I having issues with some GRP2612 that are registering with the IP public from the modem to a local UCM6304A that is the same local network. is kind of rare.

Im provisioning the phone with the Zero Config tool.

Any of you have had the same problem/issue ?



Yeah, that’s an undocumented feature


disabled nat and stun?


You solved that way ?


What or how did you setup - PBX Settings, SIP Settings and NAT page?


I have a default configuration.
I do not have a public IP/DNS declared.


Then that may be your issue.

The NAT page and settings determine how the UCM will formulate the messaging between devices. You should populate the page with your static public IP or FQDN, Check the SDP box and then enter the local LAN segments further down the page.

If the UCM sees an IP making a request it will use the settings to determine if the device is local or external. If local, it will then tell the device to use its local IP due to the request coming from an IP range that you entered for the LAN(s). If it sees a request coming from any other IP than the local LAN range, then it will tell the device to use the public IP.


Thanks a lot. I Will try.