From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: source routing - bug? Date: Wed, 15 Jun 2005 03:05:48 +0200 Message-ID: <20050615010548.GE22463@postel.suug.ch> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-net@vger.kernel.org, netdev@vger.kernel.org Return-path: To: Tim Newsham Content-Disposition: inline In-Reply-To: Sender: linux-net-owner@vger.kernel.org List-Id: netdev.vger.kernel.org * Tim Newsham 2005-06-06 15:02 > Using the netcat utility I run tests from machine A: > > $ nc -g B C 3333 > I see packets forwarded to B then on to C and the connection > completes successfully. > > $ nc -g A -g B C 3333 > I see packets forwarded over lo to A, and no further packets > are sent over lo or eth0. Machines B and C receive no packets. A 127.0.0.1 source address is considered martian by the source validation code as proposed by rfc1812. You should see warnings in the console if you have martian logging enabled. > $ nc -g B A 3333 > I see packets forwarded out over eth0 to B and then back to A > but machine A never seems to accept the packets or reply with > a SYN or RST. A will do a route lookup of [src=A dst=A] which results in your local route being returned. Again this violates rfc1812 because that route will not be a unicast route but a local one. A martian source warning should be logged if enabled.