G34 device list has false positives and negatives

If you're referring to the connected devices list in the interface, then yes it displays the devices currently connected. However, please note that you cannot add, remove, or reorder devices, as those options are not available. 

The reply around noon PST 10/16/25 from SURFboard Moderator says nothing about either down devices (stale) still appearing or up devices (online) not appearing.  Those are what I asking about.  It’s not a list of connected devices, it’s a list of devices some of which are not connected and with some connected devices not in the list.

If you're referring to the connected devices list not updating, we recommend trying the following while logged into the interface: go to Troubleshooting > Restart/Restore, then click on Restart Gateway. This will refresh the entire gateway, and afterward, check if the device list has been updated.

Thanks, that gets me halfway.  The new devices list doesn’t show down devices any more.  But nmap shows 4 up devices not in the G34 list.  Can you tell me exactly what the G34 does to build this list?  I would guess it’s not ping nor nmap since the list doesn’t equal either one.  And perhaps easier, is there a way to make it try again and see if it picks up the up devices it missed upon Restart?

Guess I see the answer.  Just wait and possibly re-log in and more devices show up.  Still hope you can tell me  exactly what the G34 does to build this list.

The Connected Devices list displays devices that are currently online. Please note that when a new device connects to the Wi-Fi, it may not appear immediately in the list. The system performs a background synchronization, and the device will show up once that process is complete.

Good, that narrows it down.  But I still would like to know (1) when and/or how often does the background 

synchronization occur and how can I tell when the last or next one is, and (2) your statement that the list displays devices that are currently online isn’t complete because devices stay on the list, as far as I know for a very long time, even when they’re no longer online, so does the G34 ever remove them from the list, how often, and how can I find out the last and the next time it will do so?  My goal is detect unwanted devices e.g. hackers.  Obviously the quicker I catch them the better chance I have of preventing harm, and learning there was a hacker days ago raises useless alarm for me.