From owner-freebsd-net@FreeBSD.ORG Wed Aug 27 14:47:15 2003 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2ECD716A4C0 for ; Wed, 27 Aug 2003 14:47:15 -0700 (PDT) Received: from lennier.cc.vt.edu (lennier.cc.vt.edu [198.82.162.213]) by mx1.FreeBSD.org (Postfix) with ESMTP id F0F5143FFD for ; Wed, 27 Aug 2003 14:47:13 -0700 (PDT) (envelope-from cgaylord@vt.edu) Received: from vivi.cc.vt.edu (IDENT:mirapoint@evil-vivi [10.1.1.12]) by lennier.cc.vt.edu (8.12.8/8.12.8) with ESMTP id h7RLlCHh520775; Wed, 27 Aug 2003 17:47:12 -0400 (EDT) Received: from CNSCKGLT (ligeti.cns.vt.edu [128.173.8.161]) by vivi.cc.vt.edu (Mirapoint Messaging Server MOS 3.3.2-CR) with ESMTP id BOR34144; Wed, 27 Aug 2003 17:47:08 -0400 (EDT) From: "Clark Gaylord" To: "'Christoffer Pio'" Date: Wed, 27 Aug 2003 17:47:08 -0400 Message-ID: <715379D39F6E534594B4B3182B6365900302EA2C@fangorn.cc.vt.edu> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Importance: Normal In-reply-to: <3F4CBA6A.5AA7DEB0@cvt.dk> cc: freebsd-net@freebsd.org Subject: RE: subnetting C class into /26 /25 /26, why can this be done? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Aug 2003 21:47:15 -0000 When in doubt, do it in binary: 0 =3D 00000000 64 =3D 01000000 128 =3D 10000000 192 =3D 11000000 As a /26 (taking as given the 24 x's not shown for the other three = octets): xxyyyyyy - y's are the host xx doesn't have the same value from 64-191 As a /25: xyyyyyy - y's are the host x doesn't have the same value from 64-191 A /26 means there are 26 bits of network and 6 bits of host; a /25 means = 25 bits of network and 7 for host. As /26's xx =3D {00, 01, 10, 11} for the four distinct values, with the = other six bits signifying the host address. As /25s x =3D {0, 1} are the two distinct values. Now, you could use 0/25 (as 0-127 all have same first = bit) and 128/26 and 192/26 as each of these network address bits (10 and 11) = stay the same through the respective block of addresses. Hopefully this helps. Clark > -----Original Message----- > From: owner-freebsd-net@freebsd.org=20 > [mailto:owner-freebsd-net@freebsd.org] On Behalf Of Christoffer Pio > Sent: Wednesday, August 27, 2003 10:04 AM > To: freebsd-net@freebsd.org > Subject: subnetting C class into /26 /25 /26, why can this be done? >=20 >=20 > Is it not possible to subnet a C class into 3 nets, like >=20 > 0-63 > 64-191 <-- Offending network (?) > 192-255 >=20 > If so, why is this? >=20 > Christoffer > _______________________________________________ > freebsd-net@freebsd.org mailing list=20 > http://lists.freebsd.org/mailman/listinfo/f> reebsd-net > To=20 > unsubscribe, send any mail to=20 > "freebsd-net-unsubscribe@freebsd.org" >=20