BIND9, DynDNS, Multiple RRs

Chris Buxton cbuxton at menandmice.com
Tue Sep 23 00:04:03 UTC 2008


First, do not use CNAME's for your name server names. That means, the  
following is wrong and will not work reliably:

abc.biz.       NS     dns1.abc.biz.
dns1.abc.biz.  CNAME  a.dyndns.biz.

Second, there's no reason to give the same name to both DSL  
connections. Just because it's the same server doesn't mean the  
outside world needs to see it as one server with two (public) IP  
addresses. Use two names.

abc.biz.       NS     a.dyndns.biz.
abc.biz.       NS     b.dyndns.biz.

Chris Buxton
Professional Services
Men & Mice

On Sep 22, 2008, at 2:54 PM, Theophanis Kontogiannis wrote:

> 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
>
>
>
>
>
>
>
>




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