We have a Draytek 2925 on the latest firmware at a customer’s site.

It uses an IP Routed Subnet to route to a public IP range to various devices around the site, and a couple of users are connected via DHCP (and as such NAT)

Literally this day it has randomly refused to route traffic to the public and private IP devices randomly, and this state is cured by a reboot.

During this state the end users have limited internet access, and trying to access the internal routers is pretty much impossible.

A reboot cures this instantly, if you wait it out it does eventually return to normal.

During this period the 2925 is always accessible, and the CPU usage is normal.

Its worked reliably for a year, but now it’s all over the place.

Any ideas?

What was the session count (if you are able to access it), ive seen something similar before on a 2925 where the session count maxed out and stop accepting connections.
Had to change the max session timeout in the cli