Getting deligated reverse done correctly

[Carl Brock Sides]

* Jymm <jymm at my-deja.com> [000630 15:47]:

> 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.

They're not following RFC 2317 (but what they're doing might work
anyway - I think). If they were following the RFC, it would look
something like this:

129.0.0.300.in-addr.arpa.  IN  CNAME  129.128-27.0.0.300.in-addr.arpa.
130.0.0.300.in-addr.arpa.  IN  CNAME  130.128-27.0.0.300.in-addr.arpa. 
131.0.0.300.in-addr.arpa.  IN  CNAME  131.128-27.0.0.300.in-addr.arpa.

Then you'll have this in your zone file for 128-27.0.0.300.in-addr.arpa.

129 IN PTR www.mydomain.com.
130 IN PTR mail.mydomain.com.
131 IN PTR ftp.mydomain.com.

However, I think what they're doing will actually work, even though they
aren't following the RFC. And you have no need to set up a in-addr.arpa
zone file, since the in-addr.arpa records are CNAMEd to hosts in
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

Don't forget those periods at the ends of the lines, though. Or your
reverse lookups will resolve to "www.mydomain.com.mydomain.com".

> The part I'm confused with is what do I name this file:
> 300.0.0.rev ???

In general, it doesn't matter what you name your zone files, as long as
the names agree with what's in named.conf.

> 
> 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?

This would come into play if your ISP were following the RFC, but
they're not. (But like I said, I think it will work anyway.)

-- 
Brock Sides
csides at autozone.com