A few Dynamic DNS questions:

I've enabled dynamic DNS by setting 'any' in 'Allow Update' for my DNS zones
and low and behold workstations have started to appear. Which is nice.
Is it workstations that are putting themselves into DNS or is our Novell
DHCP server doing it? If it's the DHCP server then I assume I can change the
'any' rule to just the IP address of the DHCP box. Would I use if
DNS and DHCP are running on the same server?

And one other thing - is there a process that removes records that no longer

Obviously I've researched all this in great detail before implementing it.