CIDR is killing my nerves

[David Tonhofer]

AFAIK, it *all* depends on how your provider has
set up things. There is no specified syntax on how to do it.
Instead the provider will set up a CNAME for the address
XXX.XXX.XXX.XXX.in-addr.arpa, and delegate to you. You will
have to take up the CNAME and map to the PTR value.

For example, I have been assigned 194.154.217.224/28.

If I want to reverse-resolve 194.154.217.225, the following
happens (I'm quoting here from a note I made up for myself to
actually know what I was doing)

SOA for 217.154.194.in-addr.arpa
...ns.ripe.net seems to be down, we use ns.eu.net
dig @ns.eu.net. 217.154.194.in-addr.arpa. SOA
217.154.194.in-addr.arpa. 84983  IN   SOA ns1.pt.lu.
dns.pt.lu.217.154.194.in-addr.arpa.
217.154.194.in-addr.arpa. 432000 IN   NS  ns1.pt.lu.

SOA for 225.217.154.194.in-addr.arpa
...we ask ns1.pt.lu
dig @ns1.pt.lu 225.217.154.194.in-addr.arpa. SOA
225.217.154.194.in-addr.arpa. 86400 IN  CNAME
225.224.217.154.194.in-addr.arpa.
224.217.154.194.in-addr.arpa. 86400 IN  SOA    dns1.synapse.lu.
dnsadmin.synapse.lu.
...225.217.154.194.in-addr.arpa. has as CNAME:
225.224.217.154.194.in-addr.arpa.
...224.217.154.194.in-addr.arpa has as SOA dns1.synapse.lu
(dnsadmin at synapse.lu)
(this means the P&T nameserver is set up so that the host addresses have
CNAMEs which
are subdomains of the subnetwork base addresses -- in our case
194.154.217.224)

PTR for  225.224.217.154.194.in-addr.arpa
...we ask dns1.synapse.lu
dig @dns1.synapse.lu 225.224.217.154.194.in-addr.arpa. PTR
225.224.217.154.194.in-addr.arpa. 28800 IN PTR  dns1.synapse.lu.

Hope this helps,

		-- David

-----Original Message-----
From: bind-users-bounce at isc.org [mailto:bind-users-bounce at isc.org]On
Behalf Of Philipp Snizek
Sent: Monday, March 05, 2001 4:05 PM
To: bind-users at isc.org
Subject: CIDR is killing my nerves



Dear list users,

There is something I don't understand. If I put into named.conf

zone "168.232.212.in-addr.arpa" IN {
....
};

all is fine but one thing:
It does do reverse lookup for /24 net instead /28 net I in fact own. So far
I understand that it doesn't work. To solve the probelm, I tried this:

zone "176-28.168.232.212.in-addr.arpa" IN {
....
};

zone "176.28.168.232.212.in-addr.arpa" IN {
....
};

zone "176/28.168.232.212.in-addr.arpa" IN {
....
};

But this doesn't work. What is the syntax for my 28Bit subnet beginning on
.176?

The ISP does not have installed a delegation. But I think this should work
without my ISP delegating the CIDR block because I must be able to
reverse-resolve other hosts in 212.232.168.0/24 network on my dns servers.
With my today's config, it doesn't do it.

Thank you
Philipp