I've had occasional reboots of my Vigor 2865ax and I finally discovered what is causing it.

I have a laptop with a 2.4Ghz wifi and every time it re-establishes the connect from sleep it triggers the router to reboot.

The log gets cleared each time so I am not sure what is using it, perhaps some advice on how to retain the log so I can get some more information?

What firmware is the 2865 running?

4.4.0 is now available and looks to be stable so far.

I had a similar issue with a laptop (Surface I think it was actually) on a 2860 last year although didn't spend any time troubleshooting.

If it's reproducible worth contacting support though.

xane wrote:
The log gets cleared each time so I am not sure what is using it, perhaps some advice on how to retain the log so I can get some more information?

If you have a PC you can leave on 24/7 (preferably wired), you can use the Remote Syslog Daemon. Draytek have a free one at https://draytek.co.uk/support/downloads/software/send/336-software/2636-syslog-470-win

(It's recently been updated to V4.7.0 - one of the highlights is better compatibility with Windows XP SP3 :o :?: )