From owner-freebsd-current@FreeBSD.ORG Mon Jan 18 23:04:58 2010 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1D0981065676 for ; Mon, 18 Jan 2010 23:04:58 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from asmtpout027.mac.com (asmtpout027.mac.com [17.148.16.102]) by mx1.freebsd.org (Postfix) with ESMTP id 0566F8FC16 for ; Mon, 18 Jan 2010 23:04:57 +0000 (UTC) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=us-ascii Received: from cswiger1.apple.com ([17.227.140.124]) by asmtp027.mac.com (Sun Java(tm) System Messaging Server 6.3-8.01 (built Dec 16 2008; 32bit)) with ESMTPSA id <0KWG005E4TG7XF50@asmtp027.mac.com>; Mon, 18 Jan 2010 15:04:56 -0800 (PST) X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 ipscore=0 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=5.0.0-0908210000 definitions=main-1001180220 From: Chuck Swiger In-reply-to: <20100118221843.GB65074@rink.nu> Date: Mon, 18 Jan 2010 15:04:55 -0800 Message-id: References: <20100118175033.7ba10de0@ernst.jennejohn.org> <20100118165537.GG81608@camelot.theinternet.com.au> <20100118221843.GB65074@rink.nu> To: Rink Springer X-Mailer: Apple Mail (2.1077) Cc: Jeff Roberson , current@freebsd.org Subject: Re: Help test softupdates journaling (SUJ) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Jan 2010 23:04:58 -0000 On Jan 18, 2010, at 2:18 PM, Rink Springer wrote: >> Because DNS hostnames can't contain underscores... ? > > That is false, they can (in fact, SVR records depend on this). However, > Jeff's blog is at http://jeffr-tech.livejournal.com/; his username > appears to be 'jeffr_tech'. Underscores appear in SRV records for the explicit purpose of not conflicting with any valid hostname: The format of the SRV RR Here is the format of the SRV RR, whose DNS type code is 33: _Service._Proto.Name TTL Class SRV Priority Weight Port Target Service The symbolic name of the desired service, as defined in Assigned Numbers [STD 2] or locally. An underscore (_) is prepended to the service identifier to avoid collisions with DNS labels that occur in nature. ...from http://www.ietf.org/rfc/rfc2782.txt. See http://www.ietf.org/rfc/rfc952.txt 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 (.). ...which was slightly modified by http://www.ietf.org/rfc/rfc1123.txt 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. Regards, -- -Chuck