> > > It seems to be intentional. In the case of dummy it certainly
> > > looks as though BROADCAST should be allowed. It is supposed to
> > > behave like a real network interface isn't it?
>
> Not all real interfaces have broadcast flag set.
> If it were true, this flag would be redundant 8)
True, but I said it should be *allowed* not set always. I can't
see any way of changing the IFF_BROADCAST flag on an interface
off hand.
Dummy interfaces are often used as place holders for interfaces
which may not always be present - such as PC Card interfaces on
lap tops. In such cases the dummy interface *must* behave like
the real interface or things break.
> > - it breaks xdm
>
> Mmm... it does not break chooser.
Sure it does. XDMCP uses broadcasts to locate servers which might
be willing to manage us. If you have no interfaces with the
broadcast flag set (such as a lap top with only lo and dummy0)
it can not see the local xdm. If my lap top is plugged in to
the network it should list only the hosts running an XDMCP server.
If I pull the PC Card so it switches to a dummy interface instead
it should still list the local machine. It doesn't because the
dummy interface does not have IFF_BROADCAST set. This is what
we consider broken about it.
> > - it's incompatible to other U*X (*BSD and Linux 2.0)
>
> Sure? BSD has not IFF_BROADCAST on loopback 8)
Neither does SCO 3.2v5 (AFAIK). However this *is* a silent change
from the 2.0 behaviour and *is* causing problems - especially
since there seems to be no obvious work around.
> > are there any other programs which might need broadcasts on lo, too ?
>
> No valid programs need broadcasts on loopback.
But there *are* programs which need to have broadcasts on at least
one non-external interface. If the *only* interface was lo it would
not be completely unreasonable to want to set IF_BROADCAST even
on that.
Mike
-- .----------------------------------------------------------------------. | Mike Jagdis | Internet: mailto:mike@roan.co.uk | | Roan Technology Ltd. | | | 54A Peach Street, Wokingham | Telephone: +44 118 989 0403 | | RG40 1XG, ENGLAND | Fax: +44 118 989 1195 | `----------------------------------------------------------------------'
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