IP addresses in NS records seem to be breaking hostname resolution
Mark_Andrews at isc.org
Mark_Andrews at isc.org
Thu Jul 18 23:52:24 UTC 2002
>
>
>
> > -----Original Message-----
> > From: bind-users-bounce at isc.org [mailto:bind-users-bounce at isc.org] On
> > Behalf Of Chris Davis
> > Sent: Wednesday, July 17, 2002 9:22 PM
> > To: bind-users at isc.org
> > Subject: RE: IP addresses in NS records seem to be breaking hostname
> > resolution
> >
> >
> > I'm afraid we have lost focus of the discussion. The discussion
> regards
> > zones with NS records that incorrectly have RDATA using IP addresses
> > rather
> > than hostnames. We are not addressing NS RDATA hostnames that do not
> seem
> > to resolve to an IP address.
> >
> > The config that started our discussion was:
> >
> > @ IN NS 209.44.8.1
> > @ IN NS 209.44.8.6
> > @ IN NS 216.90.116.7
> >
>
> Chris, It is important to remember that *all numeric* hostnames are
> legal. Hence, 209.44.8.1 is a perfectly legal hostname even though it
> does not end in a recognizable TLD. It is not named's responsibility to
> ensure that the RDATA hostname is resolvable (for all the previously
> stated reasons). If there was a TLD called "1", then we could have a
> host 209.44.8.1. I forget the RFC, but, an RFC came out that removed
> the requirement for a domain name to begin with a letter (I think to
> accommodate companies like 3Com...)
>
> Dave...
>
> [clip...]
>
Actually 209.44.8.1 isn't a hostname. Go read RFC 1123 again.
I particular the last paragraph of the discussion. The
assumption here is that atleast one label will have a alpha.
209.44.8.1.example.com is a hostname however.
Note "0xdeadbeef" is not a good hostname because it is a IP
address, see inet_aton().
Mark
2.1 Host Names and Numbers
The syntax of a legal Internet host name was specified in RFC-952
[DNS:4]. One aspect of host name syntax is hereby changed: the
restriction on the first character is relaxed to allow either a
letter or a digit. Host software MUST support this more liberal
syntax.
Host software MUST handle host names of up to 63 characters and
SHOULD handle host names of up to 255 characters.
Whenever a user inputs the identity of an Internet host, it SHOULD
be possible to enter either (1) a host domain name or (2) an IP
address in dotted-decimal ("#.#.#.#") form. The host SHOULD check
the string syntactically for a dotted-decimal number before
looking it up in the Domain Name System.
DISCUSSION:
This last requirement is not intended to specify the complete
syntactic form for entering a dotted-decimal host number;
that is considered to be a user-interface issue. For
example, a dotted-decimal number must be enclosed within
"[ ]" brackets for SMTP mail (see Section 5.2.17). This
notation could be made universal within a host system,
simplifying the syntactic checking for a dotted-decimal
number.
If a dotted-decimal number can be entered without such
identifying delimiters, then a full syntactic check must be
made, because a segment of a host domain name is now allowed
to begin with a digit and could legally be entirely numeric
(see Section 6.1.2.4). However, a valid host name can never
have the dotted-decimal form #.#.#.#, since at least the
highest-level component label will be alphabetic.
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark.Andrews at isc.org
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