From owner-freebsd-questions@freebsd.org Tue Mar 15 23:06:19 2016 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A656DAD198E for ; Tue, 15 Mar 2016 23:06:19 +0000 (UTC) (envelope-from galtsev@kicp.uchicago.edu) Received: from cosmo.uchicago.edu (cosmo.uchicago.edu [128.135.70.90]) by mx1.freebsd.org (Postfix) with ESMTP id 80E18649 for ; Tue, 15 Mar 2016 23:06:19 +0000 (UTC) (envelope-from galtsev@kicp.uchicago.edu) Received: by cosmo.uchicago.edu (Postfix, from userid 48) id 6C7D1CB8CC3; Tue, 15 Mar 2016 18:06:12 -0500 (CDT) Received: from 128.135.52.6 (SquirrelMail authenticated user valeri) by cosmo.uchicago.edu with HTTP; Tue, 15 Mar 2016 18:06:12 -0500 (CDT) Message-ID: <26023.128.135.52.6.1458083172.squirrel@cosmo.uchicago.edu> In-Reply-To: <4437rrjreh.fsf@lowell-desk.lan> References: <201603151632.14124.gfh@swampdog.co.uk> <56E84CA8.4080603@qeng-ho.org> <4D586A3A-9972-427D-B32D-90806B0C0AB7@thehowies.com> <201603152131.23144.gfh@swampdog.co.uk> <44egbbiewf.fsf@be-well.ilk.org> <4437rrjreh.fsf@lowell-desk.lan> Date: Tue, 15 Mar 2016 18:06:12 -0500 (CDT) Subject: Re: dhcpd, iscsi and a raspberry pi From: "Valeri Galtsev" To: "freebsd-questions@freebsd.org" Cc: "Guy Harrison" , "freebsd-questions\@freebsd.org" Reply-To: galtsev@kicp.uchicago.edu User-Agent: SquirrelMail/1.4.8-5.el5.centos.7 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Mar 2016 23:06:19 -0000 On Tue, March 15, 2016 5:41 pm, Lowell Gilbert wrote: > Lowell Gilbert writes: > >> I thought dhcpd would use MAC address Correct: DHCP server uses MAC address to identify clients. DHCP server can be configured to give some client (identified by MAC address) the same IP (thus making that client appear with static IP. Windoze world calls this "DHCP reservation") >> if the client didn't provide >> anything else. I'll check if I get a chance. > > Confirmed. My dual-boot machine has no special settings in the server's > dhcp.conf, and gets the same address regardless of which OS it's using. > It even offers a different hostname on each OS. If DHCP lease didn't expire, DHCP server will give client the same IP (the one that is in still valid DHCP lease for this client). This is what most likely you observe. If DHCP client never goes away from network, chance is it never will change IP (unless DHCP server is specifically configured to not give client the same IP when lease is renewed. I forgot details how it is done, I never do it on my DHCP servers). Hostname: if you are using "hostname" command it reports system hostname which is configured internally in system configuration files (which particular files depends on the system). This name will be reported no matter which IP the machine gets - except special cases, like on macintosh where machine changes it's hostname (known to the machine internally) depending on network connection. This is rare thing (and drives same person crazy, programmers who write license daemons often can not "outsmart" macintosh here). I hope this clarifies some things. Valeri ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++