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Date:      Mon, 28 Sep 2009 14:14:30 -0700
From:      Juli Mallett <jmallett@FreeBSD.org>
To:        Adam Vande More <amvandemore@gmail.com>
Cc:        freebsd-net@freebsd.org
Subject:   Re: tap dhcp
Message-ID:  <eaa228be0909281414l3762e8a1rd0e7c43457a23b0e@mail.gmail.com>
In-Reply-To: <6201873e0909281321s51e3d485i1074954d43b657d6@mail.gmail.com>
References:  <6201873e0909281321s51e3d485i1074954d43b657d6@mail.gmail.com>

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On Mon, Sep 28, 2009 at 13:21, Adam Vande More <amvandemore@gmail.com> wrot=
e:
> 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.

> kldload if_tap if_bridge
> sysctl net.link.tap.user_open=3D1
> ifconfig tap0 create
> ifconfig bridge create
> ifconfig bridge0 addm tap0 addm em0
>
> it# dhclient tap0
> DHCPDISCOVER on tap0 to 255.255.255.255 port 67 interval 6
> DHCPDISCOVER on tap0 to 255.255.255.255 port 67 interval 6
> DHCPDISCOVER on tap0 to 255.255.255.255 port 67 interval 13
> DHCPDISCOVER on tap0 to 255.255.255.255 port 67 interval 18
> DHCPDISCOVER on tap0 to 255.255.255.255 port 67 interval 18
> No DHCPOFFERS received.
> No working leases in persistent database - sleeping.
>
> Although dhclient em0 works as expected.
>
> FreeBSD it.digitecinc.net 8.0-BETA4 FreeBSD 8.0-BETA4 #2: Mon Sep =A07
> 11:26:25 CDT 2009
> vandemorea@it.digitecinc.net:/usr/obj/usr/src/sys/GENERIC
> i386
>
> Repost from questions@ several days ago.
>
> Thanks,
>
> --
> Adam Vande More
> _______________________________________________
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>



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