Poly CCX Phones and Time
Came across an annoying issue with Poly CCX Teams phones this week, so worth documenting here briefly to save others the same pain.
The phones log into Office 365 and MUST have the time accurate to within 5 minutes, otherwise they will not log on. Indeed, if they drift, they will stop working.
Out of the box, they will try and get time over NTP from time.windows.com, and fall back to north-america.pool.ntp.org.
If you do not have port 123 open to the Internet from the network where the phones will sit, then you can get them to look at an on-prem NTP server, but there is a major gotcha.
You can configure DHCP scope option 42 to point at your on-prem NTP server (usually, in a Windows environment, a local domain controller) however that's not enough - you also need to tell the phone NOT to override this setting: because out of the box, it does.
So to get a phone working in such an environment, you may need to follow these steps (assuming you do have Scope Option 42 appropriately set on your DHCP scopes).
1. Connect the phone to an 'open' network where it can get time from the Internet (because if it can't get the time, it may not even let you get it to a state where you can go into the phone menu).
2. Enable the web server on the phone. On the newer software, this is via Menu > Settings > Phone Settings > Device Settings > Admin Only > Enter default password 456 > Network Configuration > Enable the slider on Web User Interface. On older firmware the same setting is under Debug (the fact that this has moved makes it really hard talking a user through this remotely even if you've got a phone in front of you!).
3. Get the IP address off the phone - Menu > Settings > Device Settings > About (or from the DHCP server if you have access to it).
4. Open a web browser from the same network, and web onto the phone (you do need to use https). Enter 456 as the password.
5. Go to the Settings menu and expand the Time Synchronization menu, then set 'Override DHCP's sntp server' to No.
You should then be good to go.
Although it's annoying, it's only a 5 minute task, so whilst you can do this centrally by pointing the phones to an on-prem TFTP provisioning server with a small config file on it, that may not be worth the effort if you - as many environments have - only have a small handful of phones.
This 'feature' appears to apply to firmware 5.9.12 and 5.9.13 so hopefully this will be fixed at some point so the default is not to override DHCP.