Getting deligated reverse done correctly

[Kevin Darcy]

Jymm wrote:

> Please excuse any ignorance here, looking for clarification of RFC2317
>
> Running: bind-8.2.2p4 under Caldera 2.3

You're only 1 patch level away from the latest & greatest.

> My ISP assigned me a /27 subnet - (we'll say...) 300.0.0.128-159
> They will give me authority for the reverses, but when I read ORA's BIND
> (3rd ed) or RFC2317, I'm a bit confused as to what goes where.
>
> In my isp's 300.0.0.rev file they have:
>
> 129.0.0.300.in-addr.arpa.  IN  CNAME  300-0-0-129.mydomain.com.
> 130.0.0.300.in-addr.arpa.  IN  CNAME  300-0-0-130.mydomain.com.
> 131.0.0.300.in-addr.arpa.  IN  CNAME  300-0-0-131.mydomain.com.
>
> In my mydomain.com.hosts file I have:
>
> www.mydomain.com.          IN A    300.0.0.129
> 300-0-0-129.mydomain.com.  IN PTR  www.mydomain.com
>
> mail.mydomain.com          IN A    300.0.0.130
> 300-0-0-130.mydomain.com.  IN PTR  mail.mydomain.com
>
> ftp.mydomain.com           IN A    300.0.0.131
> 300-0-0-131.mydomain.com.  In PTR  ftp.mydomain.com

This is a smart way to do things, but it's a little different from
RFC 2317, so I can't blame you for being confused. They are aliasing
directly into your mydomain.com zone.

> Ok, the forwards are fine, but I need to create a reverse file:
>
> 129.0.0.300.in-addr.arpa.  IN PTR  www.mydomain.com.
> 130.0.0.300.in-addr.arpa.  IN PTR  mail.mydomain.com.
> 131.0.0.300.in-addr.arpa.  IN PTR  ftp.mydomain.com.

Um, no. You already have the PTR's where they need to be. You don't need a
"reverse file". This is why I characterize the method as "smart"; because,
unlike classic RFC 2317, it doesn't require the creation of a new zone. You
just add the PTR's to an existing zonefile, and voila! you're done. I like
it.

These reverse records are actually working, n'est-ce pas? I'd check myself,
except you obfuscated the data...

> The part I'm confused with is what do I name this file:
> 300.0.0.rev ???
>
> Where does the part about 129.128-159.0.0.300.in-addr.arpa.
> come into play here as mentioned in RFC2317?
> What file is this refering to FWD or REV?

Stop thinking in terms of forward and reverse *files* or *zones*. PTRs are
reverse *entries*. As long as the CNAMEs are in the proper places, then
whether or not the PTRs are contained in a zone under in-addr.arpa is
merely a matter of convenience. With the co-operation of your provider,
they can be contained in *any* zone(s) under your control.


- Kevin