Elementary File Syntax Question

[Kevin Darcy]

Richard wrote:

> I am configuring nameservers on a 10.0 network with 255.255.0.0 netmask. All
> the examples I can find showing PTR records in a reverse lookup file are for
> CLASS C addresses. That is, they specify a single digit (octet) for the
> address, whereas on my network I need two octets to specify a host. Can
> someone please illustrate the syntax for such a pointer record?
>
> My bootfile contains:
>     primary    0.10    10.0.rev
> and the file 10.0.rev contains:
>     50.3    IN    PTR    fqdn.
>
> This does not work.

Why would you expect it to? named has no way of automatically knowing that
there should be an "in-addr.arpa" after the "0.10". You have to tell it this.

> I did get it working using very verbose lines like
>     primary 0.10.IN-ADDR.ARPA    10.0.rev
> and
>     50.3.0.10.IN-ADDR.ARPA    IN    PTR    fqdn.
> along with replacing the "@" in SOA lines with "0.10.IN-ADDR.ARPA"
>
> Do I need this level of verbosity? Can a shorter form work for my addresses?
> Suggestions? Where can I find some examples for other than CLASS C
> addresses?

Once your named.boot line was changed, then you should have been able to use
the short "@" and "relative" names, e.g. "50.3". Did you try it that way?

Of course, you could always delegate down to a lower level, e.g.
3.0.10.in-addr.arpa. Then you could use single number relative names, just like
in the "CLASS C" examples you've seen. DNS isn't really "classful" in the same
way some old routing protocols are; you can delegate on any octet boundary you
want. The only downside is that if you have addresses in multiple /24's of
10/8, you'll need to define and maintain multiple DNS zones to contain the
reverse entries.

By the way, named.boot is what BIND 4 uses, and BIND 4 is *very* dead. Upgrade
to BIND 8.2.2-p5 or BIND 9, which use a named.conf file. named.conf has a
different syntax from named.boot, but there is a conversion utility.


- Kevin