I have two queries related to DNS configuration, would be glad if someone
takes some time out to answer them.

My System environ is Netware 5.1 SP8 patched, EDir Single Tree
Single partition, 1 master two Replicas.

All the three netware servers are on the same Private Network IP Range
DNS/DHCP ns01:

The DHCP Pool assigns a range of IP: dynamically
to workstations.

I have noticed that if someone manually tries to assign IP: on
his/her laptop or desktop(users have admin previleges on their
workstations, can't take that away), they get a message that the IP is
already in use (as it belongs to DNS Server ns01).

It's all fair till now, but my DNS server starts to go erratic. Both fs01
and fs02 starts to give message " Communication lost to ns01". Then after
sometime another message gets repeated " Established communication with
ns01". Time sync gets lost across replicas.

Users who get lease during this time are unable to resolve the names
through ns01 and that's their primary NameServer assigned via DHCP.

Q1: How can I secure my LAN or DNS Server from this malfunction.
Noticeable is the fact that the user also acquires the same IP despite
the message or IP already under use and console message on ns01,
that "another machine has requested the same IP".

How can I safe guard these network servers through rogue IP assignments
of the same number? VLAN creation is an option but not for now as I need
an inter vlan L3 switch which I have raised a request for.

Q2: How can I create a backup/redundant DNS server? The current machine
serving DNS/DHCP is quite old, I want to build a new server and slowly
take this offline once that one gets operational. Any appnote/doc TID
pointer will do in this regard?

Q3: Is there a way I can set static leases through my Netware DHCP? I
mean, once the lease gets assigned, I make it permanent by feeding in the
MAC of that hardware device, so that every time the station boots up, it
gets the same IP address lease.

Thanks in advance!