Google Nest WiFi blocking UDP port forwarding despite proper configuration

[spadez]

Description:

I'm experiencing an issue with UDP port forwarding on my Google Nest WiFi router where UDP ports are being blocked despite proper configuration, while TCP port forwarding works perfectly.

Network Configuration:

• ISP: Aussie Broadband with static public IP address
• Router: Google Nest WiFi
• Network: NBN → Google Nest WiFi → NETGEAR switch → Server on reserved IP

Issue Details:

• TCP port forwarding works perfectly (web service ports forward successfully)
• UDP port forwarding fails completely (game server ports needed)
• Ports configured individually in Google Home app with protocol set to "UDP only"
• Network restarted after each port configuration attempt
• External port testing shows "Connection timed out" for UDP ports
• Server IP address is reserved in router settings

Server Configuration (Confirmed Working):

• Ubuntu server with UFW firewall properly configured to allow required UDP ports
• iptables rules show correct UDP port forwarding
• Server listening on all required UDP ports (verified with netstat)
• Application (game server) responding correctly on local network
• ISP confirmed no UDP port blocking on their end

Troubleshooting Already Attempted:

1. Individual port configuration (not port ranges)
2. Multiple network/router restarts
3. IP address reservation for target device
4. Verified protocol set to UDP only (not TCP or Both)
5. Tested with host networking to bypass Docker bridge
6. Confirmed server-side firewall allows traffic
7. Verified no ISP-level blocking

Technical Evidence:

• Server shows listening on required UDP ports
• Firewall rules show correct ACCEPT rules for UDP ports
• TCP ports forward successfully to same server IP
• External TCP port tests pass, UDP port tests fail with timeout

Request: Please enable advanced UDP port forwarding capabilities on my Google Nest WiFi or provide guidance on resolving this UDP-specific forwarding limitation. The issue appears to be specific to the Google Nest router's handling of UDP traffic, as all other network components are verified working correctly.

Router Details:

• Google Nest WiFi Router
• Model: H2D
• Software Version: 14150.883.17
• Google Home app version: 3.35.55.0

[spadez · Accepted solution]

So it turns out UDP port testing on services like https://canyouseeme.org/  and https://www.yougetsignal.com/tools/open-ports/  don't reliably show whether a UDP port is actually open.

I ended up going into the game server I had set up on the UDP ports and it worked fine.

For anyone else having issues setting up and testing port forwarding on UDP ports, just set up the ports as expected and test the actual connection with the service you are using 🙂