From owner-freebsd-chat Thu May 27 13:25:26 1999 Delivered-To: freebsd-chat@freebsd.org Received: from shell.webmaster.com (mail.webmaster.com [209.133.28.73]) by hub.freebsd.org (Postfix) with ESMTP id 35E4314D07 for ; Thu, 27 May 1999 13:25:19 -0700 (PDT) (envelope-from davids@webmaster.com) Received: from whenever ([209.133.29.2]) by shell.webmaster.com (Post.Office MTA v3.5.3 release 223 ID# 0-12345L500S10000V35) with SMTP id com; Thu, 27 May 1999 13:25:17 -0700 From: "David Schwartz" To: "Jasper O'Malley" , "Dan Langille" Cc: Subject: RE: Mickey Mouse networking... Date: Thu, 27 May 1999 13:25:17 -0700 Message-ID: <000201bea87f$08a86840$021d85d1@whenever.youwant.to> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2377.0 In-reply-to: Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3155.0 Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org And even if you assume that Microsoft is trying to remain compatible with older classful implementations, this is class B space. So even under the old rules, forgetting about VLSM and CIDR, this address would _still_ be valid. It's clearly valid under classless rules, as already pointed out. DS > On Fri, 28 May 1999, Dan Langille wrote: > > > I understood that ip addresses ending in either 0 or 255 were not to be > > used. They are both used as broadcast addresses. Is that correct? > > An IP address with all zeros in the node bits is a network address, and an > IP address with all ones in the node bits is a broadcast address. The > trick is determining what the node bits are, and that's what subnet masks > are for. They're contiguous bitmasks that specify the network bits of a > given IP address. > > For instance, 255.255.255.0.0 in binary is > > 11111111 11111111 00000000 00000000 > > The ones bits in the mask are network bits, the zeros are node bits. If > I've got the address 10.4.100.255 with a netmask of 255.255.0.0, it looks > like this: > > 00001010 00000100 01100100 11111111 > ^---------------^ ^---------------^ > network node > > The node portion is not all ones or zeros, so it's a valid node address. > > Cheers, > Mick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message