Just replaced my 2820n with a 2830n, and just found something odd when I was setting the new box up.
I set the 2830 with ip address of 192.168.0.1 subnet 255.255.254.0 as I have a separate network on 192.168.1.0, I also set the DHCP server to issue new ip addresses in the 192.168.0.10 to 192.168.0.99 range, but for some reason, every ip address it issued was 192.168.1.x.
I released, manually set a PC to 192.168.0.10, then reset it back to DHCP controlled, and it again got the ip 192.168.1.10.
The only way to fix the problem, was to change the subnet mask to 255.255.255.0 but that stops me now connecting to the "proper" 192.168.1.x machines.
For info:
System Status
Model Name : Vigor2830n
Firmware Version : 3.3.6_232201
Build Date/Time : Nov 5 2010 10:54:23
Thanks,
-Stuart