On Wed, 23 Feb 2022 at 19:02, Adam Bower adam@thebowery.co.uk wrote:
What device is it and which version of openwrt? By default openwrt devices run ntpd to keep the clock synced, I've never had to change the default configuration as it all "just works".
It's a Teltonika router (they have a wide range of openwrt kit and their own LUCI-based GUI), bought from Solwise.
When I posted here I was waiting on a response from Teltonika support via Solwise - there'd been a bit of to-and-fro and I was becoming convinced that the problem was me (ie something I didn't understand, eg that a default config would accept a drift greater than seemed reasonable to me and I just hadn't waited long enough for it to reach the threshold for correction).
Then two things happened almost simultaneously. MJR's comment about checking ntpclient was running (there was no ntpclient process) and Teltonika sending me a new firmware version to try, which does now have an ntpclient process running and which does now maintain the clock to within around 200ms (I'm sure I can tweak that if I care, but I don't).
I don't know *why* ntpclient wasn't running on the old firmware but from comments that came with the new firmware I think it might be about connection stability so a guess would be that it was failing to start properly if the network wasn't up quickly, and this is a 4G unit so that can take some time. But that's speculation.
Anyhow, it looks like this is now working - thanks all for your input.