From owner-freebsd-questions Mon Dec 27 18: 4: 2 1999 Delivered-To: freebsd-questions@freebsd.org Received: from dorifer.heim3.tu-clausthal.de (dorifer.heim3.tu-clausthal.de [139.174.243.252]) by hub.freebsd.org (Postfix) with ESMTP id 0F18715052 for ; Mon, 27 Dec 1999 18:03:59 -0800 (PST) (envelope-from olli@dorifer.heim3.tu-clausthal.de) Received: (from olli@localhost) by dorifer.heim3.tu-clausthal.de (8.8.8/8.8.8) id DAA23875 for freebsd-questions@FreeBSD.ORG; Tue, 28 Dec 1999 03:03:58 +0100 (CET) (envelope-from olli) Date: Tue, 28 Dec 1999 03:03:58 +0100 (CET) From: Oliver Fromme Message-Id: <199912280203.DAA23875@dorifer.heim3.tu-clausthal.de> To: freebsd-questions@FreeBSD.ORG Subject: Re: arplookup Organization: Administration TU Clausthal Reply-To: freebsd-questions@FreeBSD.ORG MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: TIN [version 1.2 RZTUC(3) PL2] Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Shawn Ramsey wrote in list.freebsd-questions: > arplookup 192.216.87.246 failed: host is not on local network > > Does anyone know what that error means, and how I might fix it? I am > getting these sorts of entries on the console for numerous(maybe all) of > the workstations on that network. It most probably means that the host with the IP number 192.216.87.246 has a wrong netmask configured. For example, assume that two hosts A and B are on two different class-C networks, i.e. their "natural" netmask is 255.255.255.0. Then assume that host B has a (wrong) netmask configured which is 255.255.0.0, but it still can reach A because there's a switch or a bridge between them (or something similar) which just forwards the packets. Now when B sends a packet directly to A (without using the default route, because of the wrong netmask), A will add B to its arp table. This normally happens every time the IP stack discovers a "new" host on the network, to save ARP requests. However, the kernel will discover that B is not on its local network (according to the correct netmask), therefore the arp entry is not valid (hosts which are on other networks are only reachable through the default route [or some other route], but not directly, so they cannot have their own arp entries in the arp table of A). This is clearly an error, and so your syslog entry is generated. To fix it, you should correct the netmasks of those hosts. I hope my explanations make some sense to you. :-) Regards Oliver -- Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany (Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de) "In jedem Stück Kohle wartet ein Diamant auf seine Geburt" (Terry Pratchett) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message