From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Heffner Subject: Re: [RFC] ip / ifconfig redesign Date: Mon, 05 Dec 2005 17:19:01 -0500 Message-ID: <4394BCD5.1060505@psc.edu> References: <200512022253.19029.a1426z@gawab.com> <200512031646.45332.a1426z@gawab.com> <4391E4FC.1040200@candelatech.com> <20051205140057.GC24764@tuxdriver.com> <20051205174010.GA14101@buici.com> <43947FEB.7020504@unfix.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marc Singer , Ben Greear , Al Boldi , netdev@vger.kernel.org, linux-net@vger.kernel.org Return-path: To: Jeroen Massar In-Reply-To: <43947FEB.7020504@unfix.org> Sender: linux-net-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Jeroen Massar wrote: > I wonder how many RFC's it violates. An interface must only answer ARP's > on the interface that it is configured on, not anything else. Not true. See RFC 1122, section 3.3.4. The standard leaves this decision up to the implementation, for good reason. From 1122 (note the use of MAY, not MUST or SHOULD): " There are two key requirement issues related to multihoming: (A) A host MAY silently discard an incoming datagram whose destination address does not correspond to the physical interface through which it is received. (B) A host MAY restrict itself to sending (non-source- routed) IP datagrams only through the physical interface that corresponds to the IP source address of the datagrams. " This topic has been discussed many times on a variety of mailing lists. I think the best way to do this is to make the behavior configurable, which Linux currently does. -John