Grandstream IP Phone NAT Type UDP Blocked

Network Status NAT Type: UDP Blocked in Grandstream IP Phones

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Grandstream IP Phone NAT Type UDP Blocked

Description

The Network Status of NAT Type: UDP blocked indicates that the Grandstream IP Phone device detects that the SIP port is not port forwarded. 

Suggestions

  1. Disable the SIP ALG option in the router or firewall
  2. Configure Port Forwarding in the router
  3. Change the default SIP Port 5060
  4. Select Keep-Alive under the Account > Network Setting followed by a reboot

Please note that STUN does not work with all the routers, especially with Symmetric NAT enabled, it is recommended to do manual port forwarding for the SIP and RTP ports to avoid the problem.