On Wed, 29 Aug 2001, Peter Bieringer wrote:
> --On Wednesday, August 29, 2001 03:25:42 PM +0900 "YOSHIFUJI Hideaki
> / =?iso-2022-jp?B?GyRCNUhGIzFRTEAbKEI=?=" <yoshfuji@xxxxxxxxxxxxxx>
> wrote:
> > If a node forwards, it should announce NA with is_router set, IMHO.
>
> I had a discussion with Pekka some time ago in which he find out,
> what the settings are really do.
>
> Control the flag isRouter can be needed if a router has more than 2
> interfaces and one of them is a stub network for which the router
> should not announce that he is a router.
I understand Yoshifuji suggested a check like:
if forwarding packet to interface X
general packet forwarding must be enabled
NEW: interface X must announce IsRouter (require symmetry, unless
otherwise worked around)
(note, if you want to forward _to_ an interface, but not _from_ it --
asymmetric routing, this check would bite you. I'm not sure if this is a
scenario worth considering).
not:
if general packet forwarding is enabled
all interfaces will have IsRouter flag enabled
.. which would simplify scenarios greatly, but IMO might be an
over-simplication at least in the long term.
> BTW: afair in IPv4 (where the forwarding-per-device switch has a
> different meaning) this switch is checked on packet input on that
> device, not on output.
Probably as I don't need any hint of output device control (except for
forward netfilter hooks) in ipv4/ip_forward.c.
--
Pekka Savola "Tell me of difficulties surmounted,
Netcore Oy not those you stumble over and fall"
Systems. Networks. Security. -- Robert Jordan: A Crown of Swords
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