[ On Tuesday, July 1, 2003 at 23:18:53 (+0530), Suresh Ramasubramanian wrote: ]
> Subject: Re: Now well off-topic - was Re: [Exim] how to configure HELO/EHLO and DNS for multi-homed hosts
>
> Suresh Ramasubramanian wrote:
>
> > frodo.hserus.net. 23h57m42s IN A 202.77.223.48
> > 48.223.77.202.in-addr.arpa. 57m46s IN PTR 202-77-223-48.outblaze.com.
> >
> > The rDNS does point right back to frodo.hserus.net
>
> woops - i mean "points right back to the IP of frodo.hserus.net"
"202-77-223-48.outblaze.com" is a hostname, not an IP address. The fact
that it might look to a human as containing some kind of representation
of an IP address is irrelevant since no standard algorithm is defined
to allow a computer to notice this fact and indeed you'll find every
manner of address representation in use for these kinds of purposes.
rDNS does not, and cannot, point to IP addresses (PTRs can point to
anything, but the Reverse DNS involves PTRs in the IN-ADDR.ARPA zone,
and those PTRs in the IN-ADDR zones normally only point to canonical
host domain names, and presumably they "MUST" point to a hostname that
resolves to the same address the PTR was derived from -- the DNS is a
directed graph data structure after all).
--
Greg A. Woods
+1 416 218-0098; <g.a.woods@???>; <woods@???>
Planix, Inc. <woods@???>; VE3TCP; Secrets of the Weird <woods@???>
