Bind 8.2.2p3 and Dynamic DNS help

[Larry Hook]

We are currently using Bind 8.2.2.p3 running on 2 Solaris 2.6 machines and
everything is working fine.
We are basically a NIS shop and are using bind as a backup method of name
resolution for a unix hosts and also as a backup to WINS for our microsoft
hosts.
Nightly we use a perl script to munge the the /etc/host file to
automatically recreate the forward and reverse lookup zones for our DNS
servers. This is working fine then comes along Dynamic DNS.
We are testing a DHCP server (microsoft's) for both our unix and nt hosts.
the dynamic updates work fine both forward and reverse, but along comes the
nightly NIS update and deletes our zone files and recreates them,ouch. I can
watch named manage the *.ixfr files and update them (added and deleting
resource records and incrementing the serial number).

My questions are regarding how long the *.ixfr files last and when and how
named incorporates them into the zone files. I am thinking that I could save
the *.ifxr files nightly and then munge the serial numbers to the next days
date and replay them the after doing the nightly NIS update.

Perhaps a better solution would be have the nightly NIS update use the
dynamic DNS update calls to inject the /etc/hosts changes in the the zones
Would anyone care to comment r offer insight as to how to accomplish either
of these solutions

Thanks
Larry Hook