BIND9, DynDNS, Multiple RRs

[Theophanis Kontogiannis]

Hello All,
 

I have my DNS server, serving my .biz zone, NATed behind 2xDSL routers /
connections. 

The DNS is running on Centos 5 and bind-9.3.4-6.0.2.P1.el5_2.

The DSL modems (I have two connections) are using DynDNS since the DSL
connection is provided with dynamic DNS allocations.

We assume that modem A gets declared on DynDNS as "a.dyndns.biz." and modem
B as "b.dyndns.biz.".

 

What I try to do, is to make my NATed DNS, master for my domain (let us call
it abc.biz.)

 

On the registrar I have to declare that my primary DNS for abc.biz. is the
DNS accessible through either DSL modem.

 

I define dns1.abc.biz. as the primary DNS.

However since this a DynDNS registered IP, I have to define dns1.abc.biz. as
a CNAME to "a.dyndns.biz.". 

But there are two DSL connections for redundancy and load balancing.

So if I also define dns1.abc.biz. as a CNAME to "b.dyndns.biz." then I get
the error: 

                "multiple RRs of singleton type"

 

I googled a bit, and found out that after BIND 9.1 the multiple-cnames
directive got forced obsolete.

 

Is there any way to succeed in what I try with BIND9?

 

If I have to write the zone file in a different way, can you please explain
the way, since it is not obvious to me?

 

Thank you All for your time,

 

Theophanis Kontogiannis