nsupdate and round robin

[Victor Hugo dos Santos]

Masters,

i need setup dns with option of "round robin" and this is my actual
zone file (only relevant lines):

--------------------------------------------
$TTL 3600               ; 1 day
@       IN      SOA     mamalluca.sitio.cl.         root.sitio.com. (
                               2006112801; serial
                               7200; refresh (12 hours)
                               7200; retry (2 hours)
                               2419200; expire (30 days)
                               3600; minimum (1 day)
                               )
@       IN      NS      mamalluca.sitio.cl.
@       IN      NS      ns0.xname.org.
@       IN      NS      ns1.xname.org.

@       IN      A       200.200.200.200
@       IN      MX      10 mamalluca.sitio.cl.
@       IN      TXT     "v=spf1 a"


www     60      IN      A       200.200.200.201
www     60      IN      A       200.200.200.202
www     60      IN      A       200.200.200.203
--------------------------------------------


but my original idea was use multiples CNAMEs, for example:
--------------------------------------------
www     60      IN      CNAME      server1
www     60      IN      CNAME      server2
www     60      IN      CNAME      server3

server1    60      IN      A       200.200.200.201
server2    60      IN      A       200.200.200.202
server3    60      IN      A       200.200.200.203
--------------------------------------------

but... restarting the bind daemon with this options (multiples cnames)
i get this errors:
(now.. I understand that BIND9 not permit multiples-cnames options !!!)    :-(
--------------------------------------------
sitio.cl-local:46: TTL set to prior TTL (60)
dns_master_load: sitio.cl-local:46: www.sitio.cl: multiple RRs of singleton type
zone sitio.cl/IN/interno: loading master file sitio.cl-local: multiple
RRs of singleton type
--------------------------------------------


and now.. my system work fine con the first example (no multiples
CNAMEs), but i have a new problem !!!

i need append one new machine in this configuration, but this new
machine have one dynamic IP, for example:

www     60      IN      A       DINAMIC_IP

I'm using "nsupdate" for update the host in other zone file without round robin,
# nsupdate
> update delete www A
> update add www 60 A 200.100.50.204
> send


but, i don't know how delete/update the specific host (www 60 IN A
DINAMIC_IP) and not other www hosts for this zone with round robin
options !!!

they understand my doubt? somebody already passage by this problem?
suggestion of like solving this ???

thanks

-- 
-- 
Victor Hugo dos Santos
Linux Counter #224399