From owner-freebsd-questions@FreeBSD.ORG Wed Nov 26 05:46:31 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 59710C3E for ; Wed, 26 Nov 2014 05:46:31 +0000 (UTC) Received: from mail-lb0-x22c.google.com (mail-lb0-x22c.google.com [IPv6:2a00:1450:4010:c04::22c]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id D22C2217 for ; Wed, 26 Nov 2014 05:46:30 +0000 (UTC) Received: by mail-lb0-f172.google.com with SMTP id u10so1862236lbd.17 for ; Tue, 25 Nov 2014 21:46:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:date:message-id:subject:from:to:content-type; bh=Qd/1kXtOXzFxQYuMZ1y41pQZ0yj579ZX/T/EoIbg7GA=; b=C4wM7smvRa++eaNfH4Eyb9ZLrJTJU+yPNRZzgg5IJeRIHdabID+mrrFYWxcpfDFM/d +Coq5nQsqmKr9A8sFHbW0XrVMa+XXA7UFTXLvoTAVOCOzlktPTwPvvNl9Z7rV+5fmtPD T786Q47fOXS2mQ/CCce7F7T1LMP0+R5Scg+CSBE2VXzGWEiRFtyUpVmCIvAaBGxk5dol GcNIWxPMfacuEJujjBQfql2dOTZ58eV5n+muPy5is8xn0iEEh50WrXP2oBBqxmOZCn7h vf8M7HSPZhGMmDAxe8aatHkG0lD40vIzU8D0brPAPTXWLdHB2HSsMxADjnAatiVUsv7p hx+w== MIME-Version: 1.0 X-Received: by 10.112.234.201 with SMTP id ug9mr32444201lbc.14.1416980788992; Tue, 25 Nov 2014 21:46:28 -0800 (PST) Received: by 10.25.44.149 with HTTP; Tue, 25 Nov 2014 21:46:28 -0800 (PST) Date: Wed, 26 Nov 2014 07:46:28 +0200 Message-ID: Subject: Possible CARP routing issue From: Riaan Kruger To: freebsd-questions@freebsd.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Nov 2014 05:46:31 -0000 It seems that in some circumstances routing is not playing well with CARP. We have the following scenario. Device A --------- 192.168.1.10 Router: ------- 10.0.0.1 Device B -------- Interface 1 Virtual IP (CARP): 172.16.1.3 Interface 1 Real IP: 172.16.1.2 Routing table of device B: 0.0.0.0 10.0.0.1 192.168.1.0 10.0.0.1 etc ... When Device A pings the Real IP of Device B (172.16.1.2) we see the following ARP request packet: ARP request who has 192.168.1.10 tell 172.16.1.3 In other words pinging the real IP causes the Virtual IP to ask for the MAC address of the pinging device, even though they are not in the same subnet and there is a default route. Pinging the virtual IP does not induce this ARP request and the ping is successful. When deleting the second route from the routing table above the ARP request is not sent. I know the second route is superfluous but it is put there by third party software. The real issue is why this behavior happens with CARP. Is it an indication of some underlying problem? Riaan