From owner-freebsd-questions  Thu Sep 11 17:29:02 1997
Return-Path: <owner-freebsd-questions>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.7/8.8.7) id RAA11833
          for questions-outgoing; Thu, 11 Sep 1997 17:29:02 -0700 (PDT)
Received: (from jmb@localhost)
          by hub.freebsd.org (8.8.7/8.8.7) id RAA11810;
          Thu, 11 Sep 1997 17:28:54 -0700 (PDT)
From: "Jonathan M. Bresler" <jmb>
Message-Id: <199709120028.RAA11810@hub.freebsd.org>
Subject: Re: BIND Question
To: brandon@roguetrader.com (Brandon Gillespie)
Date: Thu, 11 Sep 1997 17:28:53 -0700 (PDT)
Cc: greg@smokey.prismnet.com, freebsd-isp@FreeBSD.ORG,
        freebsd-questions@FreeBSD.ORG
In-Reply-To: <Pine.BSF.3.96.970911145341.13683A-100000@roguetrader.com> from "Brandon Gillespie" at Sep 11, 97 02:56:46 pm
X-Mailer: ELM [version 2.4 PL24]
Content-Type: text
Sender: owner-freebsd-questions@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

Brandon Gillespie wrote:
> 
> On Thu, 11 Sep 1997, Greg Stringfellow wrote:
> 
> > Here is an interesting question, or at least to me right now.
> > 
> > I've got a customer who is trying to send mail to a particular location. The
> > hostname is "HPISD_ADMIN.HIGHLANDPARK.K12.TX.US". I remember reading
> > somewhere about the underscores in a hostname not being valid. But I just
> > can't seem  to track it down.
> 
> You are right, underscores are not a valid part of a domain name, even
> though old DNS servers would allow them (all that is valid is a-z0-9 and a
> dash, I believe).

	rfc1123 amends rfc952

rfc1123:
   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.

	rfc952.  "DOD INTERNET HOST TABLE SPECIFICATION" oct '85
	not listed in std-index.txt but referenced by rfc1123
	which is listed in std-index.txt

rfc952:
   1. A "name" (Net, Host, Gateway, or Domain name) is a text string up
   to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus
   sign (-), and period (.).  Note that periods are only allowed when
   they serve to delimit components of "domain style names". (See
   RFC-921, "Domain Name System Implementation Schedule", for
   background).  No blank or space characters are permitted as part of a
   name. No distinction is made between upper and lower case.  The first
   character must be an alpha character.  The last character must not be
   a minus sign or period.  A host which serves as a GATEWAY should have
   "-GATEWAY" or "-GW" as part of its name.  Hosts which do not serve as
   Internet gateways should not use "-GATEWAY" and "-GW" as part of
   their names. A host which is a TAC should have "-TAC" as the last
   part of its host name, if it is a DoD host.  Single character names
   or nicknames are not allowed.

jmb