Firewall ports?

The GC app has been working fine for years using WiFi to synch my devices. In a new location, using the same phone on a different gateway with a firewall, the GC app complained once about no connectivity and will no longer sync with Garmin web servers (it just displays the spinning cursor). The phone does have working connectivity for HTTP[s], DNS, and NTP, to name a popular few. It must be one or more ports being blocked by the firewall doing its job. I can open additional ports, but disabling the firewall is not an option.

It should be quite straight-forward to disclose the ports that need to be open for the GC app. Absent Garmin publishing this information, somebody must have run Wireshark or similar to find the answers. I find it somewhat remarkable that web searches in 2026 cannot easily locate this information.

0 e7andy 13 hours ago

My guess is that it only uses https (443) so everything should just work. That is why you can't find any info about any other ports.

I would do a test and turn off the firewall temporarily and see if that makes Garmin Connect to sync.

Are you blocking any outbound traffic in the firewall?

0 7494571 10 hours ago in reply to e7andy

Thanks, e7andy. That was my test - I set up a configuration where the firewall could be disabled and I successfully refreshed the app home screen, then with the firewall re-enabled, I tried to refresh it again. Fail. Yes, pretty much everything outbound is blocked *except* the ones I mentioned and the smallest handful of other ones. "normal" port 80/443 stuff works fine. The firewall unfortunately isn't logging anything for the failures, which is a different problem for another day. A working Wireshark configuration would be nice but not something I can have in the near-term.

I wonder if Garmin even knows what the toolkits they employ in their software packages are doing, because I suspect "Alphabet" or FB are doing something we wouldn't approve of.