From owner-freebsd-questions@FreeBSD.ORG Wed Nov 26 07:31:41 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 319E881B for ; Wed, 26 Nov 2014 07:31:41 +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 A605ED8A for ; Wed, 26 Nov 2014 07:31:40 +0000 (UTC) Received: by mail-lb0-f172.google.com with SMTP id u10so1962501lbd.3 for ; Tue, 25 Nov 2014 23:31:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=JiXXEk1DZ3i0ZB+6NXCs5mrAy6C7F5XSzQvyD9lyzic=; b=FHSmX5vOEzJeVslI0Gw3BLalUY6qgN0SgRcof9Fnii4rleVVAlim6HOhIWzVki2LUv umqG2q7ugv7hpgLTnwdbaNmdbCvstk9NhsqbU0eU4ATfyUvFMhAug5qkoS0a9rQWAYPU flZbZwmKQP7ump8FIQSGtLk6uPbR/9mk4M7ynoIca8e1ruc2UsRWfIBn+4Y6kXfFlZLZ J8GszogmJQck6JbRn6zDtZ7itfWt7l3GnFQxTS2UQBdSQwyoCL+o3F6ft9zo6OGAPYGO f2eaJvelGf474+EPET5ebRCcscvmRE+/75udv5E8HTlv8OrhT1q1rEKEpc5v6eEc1fhD 6xWA== MIME-Version: 1.0 X-Received: by 10.112.16.168 with SMTP id h8mr32515805lbd.41.1416987098803; Tue, 25 Nov 2014 23:31:38 -0800 (PST) Received: by 10.25.44.149 with HTTP; Tue, 25 Nov 2014 23:31:38 -0800 (PST) In-Reply-To: <54757216.5090502@gmail.com> References: <54757216.5090502@gmail.com> Date: Wed, 26 Nov 2014 09:31:38 +0200 Message-ID: Subject: Re: Possible CARP routing issue From: Riaan Kruger To: jd1008 Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 Cc: freebsd-questions@freebsd.org 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 07:31:41 -0000 Thank you for response. I just found the problem. The third party software installs a route (the second one listed in the above routing table) with the flags US and thereby leaving out the G flag which states "Destination requires forwarding by intermediary". This means that it assumes the destination is local and therefor doing the ARP request On Wed, Nov 26, 2014 at 8:24 AM, jd1008 wrote: > > On 11/25/2014 10:46 PM, Riaan Kruger wrote: > >> 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 >> _______________________________________________ >> freebsd-questions@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-questions >> To unsubscribe, send any mail to "freebsd-questions- >> unsubscribe@freebsd.org" >> >> Did you enable forwarding? > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions- > unsubscribe@freebsd.org" >