From owner-freebsd-questions@FreeBSD.ORG Thu Mar 18 09:19:52 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 90F81106564A for ; Thu, 18 Mar 2010 09:19:52 +0000 (UTC) (envelope-from m.seaman@infracaninophile.co.uk) Received: from smtp.infracaninophile.co.uk (gate6.infracaninophile.co.uk [IPv6:2001:8b0:151:1::1]) by mx1.freebsd.org (Postfix) with ESMTP id 01FC28FC1D for ; Thu, 18 Mar 2010 09:19:51 +0000 (UTC) Received: from seedling.black-earth.co.uk (seedling.black-earth.co.uk [81.187.76.163]) (authenticated bits=0) by smtp.infracaninophile.co.uk (8.14.4/8.14.4) with ESMTP id o2I9Info031224 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Thu, 18 Mar 2010 09:18:49 GMT (envelope-from m.seaman@infracaninophile.co.uk) Message-ID: <4BA1EFF8.7030907@infracaninophile.co.uk> Date: Thu, 18 Mar 2010 09:18:48 +0000 From: Matthew Seaman Organization: Infracaninophile User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-GB; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: Peter Steele References: <7B9397B189EB6E46A5EE7B4C8A4BB7CB3B27DFDA@MBX03.exg5.exghost.com> <4BA1E51F.20304@infracaninophile.co.uk> In-Reply-To: <4BA1E51F.20304@infracaninophile.co.uk> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.95.3 at happy-idiot-talk.infracaninophile.co.uk X-Virus-Status: Clean X-Spam-Status: No, score=-1.1 required=5.0 tests=BAYES_00,DKIM_ADSP_ALL, SPF_FAIL autolearn=no version=3.3.0 X-Spam-Checker-Version: SpamAssassin 3.3.0 (2010-01-18) on happy-idiot-talk.infracaninophile.co.uk Cc: "freebsd-questions@freebsd.org" Subject: Re: Generating a random hostname X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Mar 2010 09:19:52 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 18/03/2010 08:32:31, Matthew Seaman wrote: > On 17/03/2010 22:06:30, Peter Steele wrote: >> Is there any facility in FreeBSD for generating a random hostname? We >> have a template with a fixed hostname that has to be changed after >> the template is closed. It would be useful to have a hostname >> generated randomly. > > perl -le '@a=(a..z,0..9); print map {$a[rand @a]} (1..8)' > > That gives you 2,821,109,907,456 different possibilities so you should > be able to use it for a while without too much fear of duplicates. Thinking about this some more, a good trick would be to generate a hostname from the MAC address of the host, since that is guaranteed to be unique. Something like this: % cat hngen #!/usr/bin/perl use strict; MAIN: { use integer; my @a = ( 'a' .. 'z' ); my $mac = shift; my $n = ''; $mac =~ tr/://d; $mac = hex $mac; # Convert to decimal integer while ( $mac > 0 ) { $n = $a[ $mac % @a ] . $n; $mac /= @a; } print "$n\n"; } % ./hngen 00:40:05:a5:8d:b7 bigdehkkt It does mean that hosts from the same manufacturer will tend to have similar names -- this might be construed as a feature... Cheers, Matthew - -- Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard Flat 3 PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate Kent, CT11 9PW -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.14 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkuh7/gACgkQ8Mjk52CukIz4egCfc6ErdXCEhIYz3emGZmPN51YX iYAAnjbBxLaAOh6pAUkfgdgZH/PyU/EM =KZ8m -----END PGP SIGNATURE-----