Subject: Re: networking with mol
From: R Shapiro (reshapiro@mediaone.net)
Date: Fri Nov 03 2000 - 06:08:39 MST
Gérard Degrez writes:
> * I understand that it's possible to set up a virtual LAN consisting
> of MOL/LinuxPPC via the virtual etertap device.
As long as you don't want to use it for lpr :)
> Question: how does one choose the IP addresses of the LAN? Is it
> arbitrary or are there rules to follow? In the mail by Takashi Oe in
> Brad Midgley's MOL FAQ, LinuxPPC and MOL are assigned the IP numbers
> 192.168.0.1 and 192.168.0.2 respectively. Can these same numbers be
> used?
There are 3 sets of address ranges specifically set aside for private
lans: one for class A, class B and class C networks respectively:
A: 10.0.0.0
B: 172.16.0.0 through 172.31.255.255,
C: 192.168.0.0 through 192.168.255.255
[class A nets have 3 bytes available for hosts, class B nets have 2
bytes available for hosts, class C nets have 1 byte available for
hosts].
You can choose any network from this category for your pseudo-lan.
With less than 256 hosts, you might as well use one of the class C
nets, the first of which is 192.168.0.
Once you choose a net address, you can pick any specific host
addresses you want net. Using x.x.x.1 for the ethertap router and
x.x.x.2 for MacOS is typical. This is why the example uses
192.168.0.1 and 192.168.0.2.
Note that the first address here isn't really the ip address for linux
as such, it's the address for a kind of router running on the ethertap
device. The assumption is that linux also has a real address on
another device (eth0 or ppp or whatever), which is what the router is
routing to. Masquerading rules on this other device are what allows
MacOS to communicate to the internet at large.
> * Takashi Oe mentions he builds a kernel with ethertap and masquerade
> supports (the latter to be able to bridge between the LAN and a PPP
> connexion. Don't mol patched kernels include ethertap support by
> default?
I'm not sure I underdstand the question. MOL supports ethertap if and
only if your linux kernel supports it.
> * If I want to run AppleTalk between MOL and LinuxPPC, I need to use
> tap0 as the network interface for netatalk.
Is that true? I don't know...
> From what I could understand from a message of Samuel Rydh, this
> requires that the tap device be recompiled with multicast support,
> right? Could someone give me detailed instructions on how to do
> this?
Can't answer this one either, but I'm wondering the same thing.
> * Finally, I guess that the virtual LAN could also be bridged to an
> ethernet network as schematized herebelow, isn't it?
> >
> > +----------------------------------------------+
> > Mac OS/MOL <-+-> tap0 <--> IP masquerade <--> eth0 <-+-> ethernet
> > 192.168.0.2 | 192.168.0.1 static IP address |
> > +----------------- Linux/PPC ------------------+
Exactly, this is the whole point of ethertap as I understand it.
> I admit that a much simpler solution is to have a second static IP
> address for MOL, but I am wondering whether the pevious solution
> would work.
Definitely simpler if you have a second address available.
-- reshapiro@mediaone.net
This archive was generated by hypermail 2a24 : Fri Nov 03 2000 - 06:08:38 MST