Understanding Network Status_ NAT Type 'UDP Blocked' in Grandstream IP Phones

Understanding Network Status: NAT Type ‘UDP Blocked’ in Grandstream IP Phones

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Understanding Network Status_ NAT Type 'UDP Blocked' in Grandstream IP Phones

Description

The Network Status indicating “NAT Type: UDP Blocked” means that the Grandstream IP Phone has detected that the SIP port is not properly port forwarded.

Figure 1 shows the Network Status, indicating that the NAT type is set to ‘UDP Blocked’

Suggestions

  1. Disable SIP ALG: Turn off the SIP ALG option in your router or firewall.
  2. Configure Port Forwarding: Set up port forwarding for the necessary SIP ports on your router.
  3. Change SIP Port: Consider changing the default SIP port from 5060 to another port.
  4. Enable Keep-Alive: Under Account > Network Settings, select “Keep-Alive” and then reboot the device.

Note: STUN may not work with all routers, particularly those with Symmetric NAT enabled.

References

SIP ALG and why it should be disabled on most routers

What is SIP ALG and Why Do You Need to Disable It?

SIP ALG: What Is It & Why VolP Users Should Disable It

What is SIP ALG and Why You Need to Disable It