From owner-freebsd-questions@FreeBSD.ORG Wed Aug 15 13:07:54 2007 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 C415E16A469 for ; Wed, 15 Aug 2007 13:07:54 +0000 (UTC) (envelope-from lflacayo@cps.k12.il.us) Received: from mail168.messagelabs.com (mail168.messagelabs.com [216.82.253.195]) by mx1.freebsd.org (Postfix) with SMTP id 8A53213C45A for ; Wed, 15 Aug 2007 13:07:54 +0000 (UTC) (envelope-from lflacayo@cps.k12.il.us) X-VirusChecked: Checked X-Env-Sender: lflacayo@cps.k12.il.us X-Msg-Ref: server-8.tower-168.messagelabs.com!1187183272!6454108!1 X-StarScan-Version: 5.5.12.11; banners=-,-,- X-Originating-IP: [209.175.45.107] Received: (qmail 17639 invoked from network); 15 Aug 2007 13:07:52 -0000 Received: from external45-107.cps.k12.il.us (HELO smtp.cps.k12.il.us) (209.175.45.107) by server-8.tower-168.messagelabs.com with SMTP; 15 Aug 2007 13:07:52 -0000 Received: from co-xmb11.admin.cps.k12.il.us ([10.129.162.211]) by smtp.cps.k12.il.us with Microsoft SMTPSVC(6.0.3790.1830); Wed, 15 Aug 2007 08:07:52 -0500 X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Date: Wed, 15 Aug 2007 08:07:50 -0500 Message-ID: In-Reply-To: <200708150210.l7F2A9iU007894@banyan.cs.ait.ac.th> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Question about failover with ISC DHCP Thread-Index: Acfe4XWkZ1L6d33fSIy6Yuj0HMGvqAAWy8yw References: <200708150210.l7F2A9iU007894@banyan.cs.ait.ac.th> From: "Lacayo, Luis F" To: "Olivier Nicole" X-OriginalArrivalTime: 15 Aug 2007 13:07:52.0153 (UTC) FILETIME=[49719C90:01C7DF3D] Cc: freebsd-questions@freebsd.org Subject: RE: Question about failover with ISC DHCP 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: Wed, 15 Aug 2007 13:07:54 -0000 Oliver,=20 Thank you very much for your prompt reply.=20 Each school is allocated 16 class C's, (hopeful thinking that one day each student will have a computer) but they are not all configured. We only configure them as they need them, the largest school has only 5 class C's configured for their subnet.=20 I will run as you suggest, and let you know.=20 Thanks again. Luis -----Original Message----- From: Olivier Nicole [mailto:on@cs.ait.ac.th]=20 Sent: Tuesday, August 14, 2007 9:10 PM To: Lacayo, Luis F Cc: freebsd-questions@freebsd.org Subject: Re: Question about failover with ISC DHCP Hi Luis, > I am looking to replace my current DHCP server with the ISC. Right now > I have to servers which are working with split scopes. Some of my > schools need over 600 IP's, so I have the school with a 255.255.240.0 > which give them 16 Class C, network, so to avoid conflicts I assign the > 3 lower to one server and the 3 highest to the other.=3D20 This part is really not clear: you have 16 class C, and you assing 3 and 3? What about the 10 others? > Now comes the question, in the following section there is a split of > 128. If I give a range of 3 class C's do I set this value to 128 or > (128*# Class C Networks)? =3D20 Fron man dhcpd.conf The split statement split index; The split statement specifies the split between the primary and sec- ondary for the purposes of load balancing. Whenever a client makes a DHCP request, the DHCP server runs a hash on the client identifica- tion. If the hash comes out to less than the split value, the pri- mary answers. If it comes out to equal to or more than the split, the secondary answers. The only meaningful value is 128, and can only be configured on the primary. This is certainly not giving much information, but they suggest you use 128, so try with 128 first. I'd suggest that you let the load balancing run for a while, then you can see how many clients are served by each DHCP server and you may try to fine adjust the split value. I have been using fail-over while I was preparing a new DHCP server recently (so the clients could start using the new server and the leases were transfered from the old to the new machine) and it was really seamless. Best regards, Olivier