Re: plip with mulinux

From: Michele Andreoli (
Date: Sun Sep 03 2000 - 10:31:28 CEST

On Sat, Sep 02, 2000 at 07:30:19PM +0200, Sven Conrad nicely wrote:
> > > Because, in this case, have to scan any configured
> > > interface and ask the user for netmask/gateway/broadcast
> No good Idea, because netmask/interface is setup stuff!
> Netmask/gateway is routing. This is totaly different! Don't
> mix this up. The easy going one interface/network stuff,
> netmask is in both cases identical, but only in this special
> case.

Ok. This is what was intended.

> >
> > I don't think so. It seems to me that a gateway is global to all the interfaces. It is set
> > up with
> Nope. Gateway routes can only address ONE interface per route. You can
> have as
> manny routes per inferface as you like.

So, routing is a per-interface setting? I've to put them in, where
x: plip ... eth?

> > I think not, finally. I think that as this stuff will only be usefull for experimented
> > users, it won't need more help messages.
> >
> Ok, what do we want? Much advaced netwok setup, but only understandable
> by experts?

The problem is how to centralize the helps screen about recurrent
network parameters as NETWORK, etc. Only a shell scripting problem.

> > > Yes. I summarized with the keyword (peer?) any special parameters
> > > for ppp/plip.
> >
> ppp is allmost a point-to-point but there is one problem. It is a
> protocoll to handle
> all ip stuff by it's own. So it call itself ipconfig. This is a big
> difference between
> ppp and plip. I nerver tryed out, if you can setup a serial line without
> pppd and
> more like plip.

Yes, it is true: pppd setup itself a route, when link is make up, but only
if "defaultroute" parameter is on. Not a true problem, because the net
effect is the same.

> > Yes, but I also think that it is not usefull to setup a network for plip in the interface
> > setup, as it is quite unusual.
> >
> I gues the oposite. plip is a usual interface. You can do everything.
> E.g. I have
> done a connect from a eth-subnet to a big LAN with the WAN behind over
> just one
> plip. Impressing, I guaratee. It's fast enought for runnung X over it.

I agree. I used NFS over plip. We can setup plip in the same way we
setup an eth.

> > > Please, discuss this topics:
> > >
> > > 1. I have to ask for netmask and broadcast for ANY interface?
> >
> Only for bus(eth) interfaces. Neither plip nor ppp have a netmask or
> broadcast.

But, why, why mon dieu? I can't route a network over plip, caused by
the point-to-point specification?

> > > 3. the 'route' command istruct the kernel to move packet toward
> > > a specific interface, based on netmask. Now, is the ipfwadm
> > > command enough to fix rules moving packets from an
> > > interface to another, and what is the common policy?
> > >
> Try to change your standpoint. There is nothing like a link between
> interfaces.

It is strange, but I can better understand "ipfwadm", compared to "route".
Can I imagine the "route" as a function like


or this scenario is intrinsecally wrong?


I'd like to conclude with a positive statement, but I can't 
remember any. Would two negative ones do?       -- Woody Allen
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