[Pdns-users] CNAME /24 block

[Damian Gerow]

Thus spake James (admin at oxygenshell.com) [22/09/03 15:07]:
> I cant do this casue im not deligating a full class of ips, just like 128
> ips and not the full class c.

That's contradictory to what you initially asked:

> > > I have a company that needs CNAMEs to his whole /24 block of ips. How
> > > would i do this with 1 step and not 256 steps.

led me to believe that you wanted to CNAME the whole /24.  I was wondering
where the CIDR bit came from.

I know there's an RFC for this, and I've been meaning to chase it down for
the past week, but does PowerDNS understand CIDR?  And perhaps CIDR
delegations (i.e. pdns does 10.0.0.0/30, customer a does 10.0.0.4/30,
customer b does 10.0.0.8/29...)?

But back to your question...

This /will/ work the way you want it to.  I believe that the '*' matches all
currently non-entered records.  So if you have the first /25 of the /24 that
you want to resolve to the same address/CNAME, that should work (but see
bert's message about wildcards from earlier today).  Then any more-specific
IN PTR records you stick in will override the wildcard.

So, using BIND-style formatting:

    *	IN PTR	devnull.example.org.
    6	IN PTR	mail.example.org.
    128	IN PTR	www.example.org.
    143	IN PTR	ftp.example.org.

Means that everything *but* .6, .128, and .143 will resolve to
'devnull.example.org.'.

Note that this is all from what I understand of the theory, feel free to
correct me, and YMMV in practice.

  - Damian