dns & subdomains

[Barry Margolin]

In article <38B583A1.B013F8A1 at home.com>, Melvin Toy  <mwtoy at home.com> wrote:
>Hi-
>
>I'm experimenting with DNS in a network using subdomains.  I based lot
>of my information on the book DNS & BIND by Albitz and Liu. I have some
>linger questions and I'm wondering what is the acceptable way in a real
>environment.  I have 13 machines.  4 per subdomain and 1 used as a
>router. My parent is the following:
>
>    comics.com - 172.16.88.1- 172.16.95.254    255.255.248
>    db.comics db.172.16 db.127.0 db.cache
>
>My other 2 subdomains are the following:
>
>avengers.comics.com    172.16.72.1 -172.16.79.254 255.255.248.0
>db.avenger db.172.16 db.127.0 db.cache
>
>xmen.comics.com          172.16.80.1 - 172.16.87.254 255.255.248.0
>db.xmen db.172.16 db.127.0 db.cache
>
>Each subdomain has a master and slave nameserver. I add the NS and glue
>records to comics.com master nameserver.  Everything works fine. What I
>can't do is resolve anything in comics.com from within
>avengers.comics.com and xmen.comics.com.  The book is not clear on
>this.  It does mention making the master of each subdomain (xmen &
>avengers) a slave of the entire zone (comics). Xmen and avenger's master
>
>would have copy of db.comics.  I can now resolve names in comics from
>with xmen and avengers but I can't do a reverse lookup.  I can't just
>make each
>master a slave and have the db.172.16 copied because it would write over
>
>each master db.172.16.  So is the solution to make each master a slave
>for comics.com and not transfer a copy of comic's db.172.16.  Would this
>
>be a valid and viable solution? I could rename each db.172.16 but if I
>decide to use h2n it sort of defeats the purpose of using the script.

Since each subdomain also corresponds with different subnets of 172.16, you
should should break up the reverse domain.  Instead of db.172.16 you should
have db.172.16.88 through db.172.16.95 for comics.com, db.172.16.72 through
db.172.16.79 for avengers, and db.172.16.80 through db.172.16.87 for xmen.

You would also need db.172.16 that contains delegation records for the
subdomains.  The comics.com server should probably be master for this, and
the subdomain servers can be slaves.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
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