Make aliases that don't transfer?

John Wobus jw354 at cornell.edu
Mon Apr 2 18:58:54 UTC 2007


If I understand, you have multiple (perhaps many) zones that use the 
same zone file, and it seems unnecessary to
transfer all the zone data for each zone, when it is the same file.

It may seem unnecessary, but it is necessary.  The means provided to 
create a zone file that does not include
its own full name is a convenience for your configuration efforts.  All 
those full names are generated as
the zone data is read into Named, and are necessary for the service.  
The actual DNS protocol, not only for
DNS lookups, but for zone transfers as well, passes the full names over 
the wire.  (The protocol does utilize
abbreviations for the sake of compression, but not the scheme you see 
in the zone files.)

If you truly need to cut down on traffic or disk space, and if you run 
all the relevant nameservers, you could forget
about DNS master/slave zone transfers, and use rsync or some such file 
transfer protocol to keep all your authoritative
servers' zone data in synch.  Then a single file transfer could serve 
for many zones, and all the nameservers
would only have to store one such zone file.

John Wobus
Cornell CIT

On Apr 2, 2007, at 10:30 AM, Jeff Lightner wrote:

> We have multiple domains that are aliased to our main domain.   This
> works fine.
> I've noticed on doing zone updates and transfers from master to slave
> that it essentially transfers the alias zone file for EACH aliased
> domain.   This seems unnecessary since the zone file is a single one 
> for
> all these domains so it seems the transfer for the first alias should 
> be
> sufficient.   I was curious how I would insure it only transferred 
> once.
> Is there a type other than "master" or "slave" or should I just take 
> out
> the "allow transfer" line?   I don't want to delete the entry entirely
> from the slave for obvious reasons.
>
> Example from my master:
> zone "4waters.com" {
>         type master;
>         file "watercom-aliases";
>         allow-transfer { watercom; };
> };
>
> From my slave:
> zone "4waters.com" {
>         type slave;
>         file "watercom-aliases";
>         masters { 10.0.21.21; };
>         allow-transfer { watercom; };
> };
>
>



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