From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists.gentoo.org ([140.105.134.102] helo=robin.gentoo.org) by nuthatch.gentoo.org with esmtp (Exim 4.43) id 1EARQp-00079X-Bl for garchives@archives.gentoo.org; Wed, 31 Aug 2005 12:11:07 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.13.4/8.13.4) with SMTP id j7VC5Mb9007157; Wed, 31 Aug 2005 12:05:22 GMT Received: from mail.t-systems.cz (mail.t-systems.cz [212.67.76.249]) by robin.gentoo.org (8.13.4/8.13.4) with ESMTP id j7VBrrhb030830 for ; Wed, 31 Aug 2005 11:53:53 GMT Received: from mefisto.t-systems.cz (faust.t-systems.cz [10.246.110.12]) by mail.t-systems.cz (Postfix) with ESMTP id F17468998E for ; Wed, 31 Aug 2005 13:56:02 +0200 (CEST) Received: from andre.t-systems.cz ([10.246.112.240]) by mefisto.t-systems.cz with Microsoft SMTPSVC(6.0.3790.211); Wed, 31 Aug 2005 13:56:02 +0200 Received: andre.t-systems.cz 10.246.112.240 from 10.246.112.176 10.246.112.176 via HTTP with MS-WebStorage 6.5.6944 Received: from frankies by andre.t-systems.cz; 31 Aug 2005 13:56:08 +0200 Subject: Re: [gentoo-user] [OT] Finding other machines on the network From: Frank Schafer To: gentoo-user@lists.gentoo.org In-Reply-To: <42BDB8AE-9479-40BA-9660-4E0BC9920B40@jolet.net> References: <43147285.1090009@wht.com.au> <43147763.802@gmx.ch> <200508301018.52929.john@jolet.net> <4314D63F.7030303@gmx.ch> <12CAFC93-126B-48E9-9F5B-40A0D60B6F96@jolet.net> <1125470325.6068.0.camel@localhost.localdomain> <42BDB8AE-9479-40BA-9660-4E0BC9920B40@jolet.net> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Wed, 31 Aug 2005 13:56:07 +0200 Message-Id: <1125489368.5869.11.camel@localhost.localdomain> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@gentoo.org Reply-to: gentoo-user@lists.gentoo.org Mime-Version: 1.0 X-Mailer: Evolution 2.2.1.1 X-OriginalArrivalTime: 31 Aug 2005 11:56:02.0778 (UTC) FILETIME=[F5E9ABA0:01C5AE22] X-T-Systems_Czech-MailScanner: Found to be clean X-T-Systems_Czech-MailScanner-SpamCheck: not spam (whitelisted), SpamAssassin (score=-5.845, required 5, autolearn=not spam, ALL_TRUSTED -3.30, AWL 0.05, BAYES_00 -2.60) X-MailScanner-From: frank.schafer@t-systems.cz X-Archives-Salt: a6b00fb6-b63f-48be-9bc2-7cdf7bc5f124 X-Archives-Hash: 966b9f45d3181bf6dde30f832ec480d6 If some other machine wants to communicate with some second other machine ... say secmachine.homenet.com it connects to the DNS server of homenet.com. (This step won't be done if IP addresses are in use. The DNS server then sends the IP address to firstmachine.homenet.com or firstmachine uses the known one. Next firstmachine will broadcast an "ARP whois ip.of.sec.srv" request. sec.srv or secmachine will answer with an ARP reply which contains the IP and the MAC address. Firstmachine then initiates the communication using this MAC address. Don't forget. The transport layer is ETHERNET. There don't exist IP addresses. Just for clarification. arp will do exactly this and arpd can even collect such information because every machine on a subnet will see all of the requests and replies. Regards Frank On Wed, 2005-08-31 at 05:50 -0500, John Jolet wrote: > On Aug 31, 2005, at 1:38 AM, Frank Schafer wrote: > > > > > ... what about arp? > > > > If this machine has the mac address listed on the outside of the > case, or he opens it up to look at the card, sure. if you don't know > what the mac address is....then you're stuck. Of course, if it's a > small, home network, you could always just turn off all the other > computers except that one and the one you're on and ask the router > who's connected. be quicker just to launch nmap and go get some coffee. -- gentoo-user@gentoo.org mailing list