Subject: Re: wireless / dhcp
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: current-users
Date: 02/17/2000 15:27:31
>>> If you have "ep0" and "ppp0" in your kernel, then dhcp would only
>>> try on the one that coincidentally also was a physical interface.
>> In what way is ep0 any more a physical interface than ppp0?  (I
>> guess what I'm really asking here is, what does "physical interface"
>> mean?)
> That's not the point.  It won't try ppp0 since it isn't broadcast.

Well, yes, that's the point wrt DHCP.  I was trying to inquire what
people thought "physical interface" meant.

> There are no other broadcast interfaces (sl, ppp, tun, gre, and ipip
> are all point2point).

tun, at least, can change between p2p and broadcast - see the
TUNSIFMODE ioctl.  And there's no conceptual reason a SLIP interface
shouldn't be treatable as a broadcast-capable network; if it's run over
a normal serial line, the hardware is point-to-point - but heck, so is
10baseT; it's the hub/switch in the middle that creates the illusion of
a broadcast network, and the same could be done with SLIP encapsulation
and a box with lots of serial ports.

> There is "strip?", which is broadcast, and would correspond to a
> physical interface,

There you go again.  What is this "physical interface" notion you keep
tossing around so blithely?

> dhclient should really ignore interfaces which don't have a carrier
> (and pay attention to them on a rising edge), but I don't think we
> have that info available to userspace programs yet.

Depending on exactly what you want, the routing socket may give it to
you.  It exposes a whole lot of otherwise-kernel-internal events.

					der Mouse

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