Date: Mon, 28 Sep 2009 16:50:47 -0500 From: Adam Vande More <amvandemore@gmail.com> To: Juli Mallett <jmallett@freebsd.org> Cc: freebsd-net@freebsd.org Subject: Re: tap dhcp Message-ID: <6201873e0909281450x2d457608yd0548db12fb21a97@mail.gmail.com> In-Reply-To: <eaa228be0909281414l3762e8a1rd0e7c43457a23b0e@mail.gmail.com> References: <6201873e0909281321s51e3d485i1074954d43b657d6@mail.gmail.com> <eaa228be0909281414l3762e8a1rd0e7c43457a23b0e@mail.gmail.com>
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On Mon, Sep 28, 2009 at 4:14 PM, Juli Mallett <jmallett@freebsd.org> wrote: > On Mon, Sep 28, 2009 at 13:21, Adam Vande More <amvandemore@gmail.com> > wrote: > > Am I doing something wrong here? > > That depends on what you're expecting to happen. What do you think > tap(4) does and what are you trying to accomplish with using it? > Interface bridging controls what happens on packet ingress =97 when a > packet comes in on one side of the bridge it is forwarded out the > other. When dhclient(8) sends out a DHCPDISCOVER on tap0, that goes > through the interface output routine. tap(4) works such that then > would go to a user-space process reading from tap0 and then that > process would forward it on to somewhere else where eventually it > might find a DHCP server. If it does, the DHCP reply would come back, > that user-space process would inject it into the kernel and the > bridging code would pass it out em0. > > I don't entirely understand, let's try a different example. Say we start with the same logical setup minus DHCP: kldload if_tap if_bridge sysctl net.link.tap.user_open=3D1 ifconfig tap0 create ifconfig bridge create ifconfig bridge0 addm tap0 addm em0 Suppose em0 is at 192.168.0.10 and another system 192.168.0.1. Then I can manually assign 192.168.0.11 to tap0 and enter this: ping -S 192.168.0.11 192.168.0.1 Should I recieve a response? From tap(4), and other examples my understanding is yes, but that is not what I'm seeing in practice. Forgive my ignorance, but wouldn't bridge0 pass a response back to tap0? My goal is essentially clone my network connection recieving two DHCP lease= s to the same box. Also I am aware of ifconfig alias, but that didn't seem u= p to the task. --=20 Adam Vande More
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