From owner-freebsd-chat Thu May 27 13:14:28 1999 Delivered-To: freebsd-chat@freebsd.org Received: from mercury.webnology.com (mercury.webnology.com [209.155.51.2]) by hub.freebsd.org (Postfix) with ESMTP id 6BD3B159D3 for ; Thu, 27 May 1999 13:14:24 -0700 (PDT) (envelope-from jooji@webnology.com) Received: from localhost (jooji@localhost) by mercury.webnology.com (8.9.2/8.9.2) with SMTP id OAA30637; Thu, 27 May 1999 14:15:57 -0500 (CDT) Date: Thu, 27 May 1999 14:15:57 -0500 (CDT) From: "Jasper O'Malley" To: Dan Langille Cc: freebsd-chat@freebsd.org Subject: Re: Mickey Mouse networking... In-Reply-To: <19990527195622.QKUY7623210.mta2-rme@wocker> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org 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 The Reverend Jasper P. O'Malley dotdot:jooji@webnology.com Systems Administrator ringring:asktheadmiral Webnology, LLC woowoo:http://www.webnology.com/~jooji To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message