D'oh!

[Lennart Sorensen]

On Tue, Dec 11, 2007 at 01:58:48PM -0500, chris-n/jUll39koHNgV/OU4+dkA at public.gmane.org wrote:
> Interesting that on another machine (ubuntu as well) the entire contents of 
> /etc/network/interfaces is, 
> 
> auto lo
> iface lo inet loopback 
> 
> It doesn't have an entry for an Internet connection at all - yet I have 
> Internet connectivity. It makes you wonder if this file is being referred 
> to at all (for Internet, anyway). 

It probably uses network manager along with udev and simply runs dhcp by
default on any interface that doesn't have a configuration.

> Well, my router documentation instructed that the gateway (router address) 
> is 192.1.68.0.1 

Sure, IF that router is your internet connection.  If it is not, then
that router isn't really the router.  I have run a wireless router in
the past with nothing connected to the WAN port, and just connected the
machines to the switch ports and then used one of those machines as the
gateway with the internet connection attached directly to it.

> Okay, thanks. Now I have to configure a third computer with local address 
> so it can print to the printer at another machine. Based on my 
> understanding of your instructions, can I add these lines to it's 
> /etc/network/interfaces file?: 
> 
> iface eth1 inet static
> address 192.168.0.4
> netmask 255.255.255.0 

Well that ought to work.  Assuming it is a debian like system that is.

You can have either:

internet --- eth1 [PC working as gateaway] eth0 --- switch/wifi AP/router --- other machines
in which case eth1 would run dhcp or pppoe or whatever the connection
needs, and either the switch/router runs dhcp but configured to use the
eth0 address as gateway, or you disable dhcp server on the switch/router
and run it on the gateway PC instead (which is what I have done) and
let it assign the eth0 as gateway to the local dhcp clients.  In your
case it actually sounds a bit like you aren't using dhcp at all on your
switch/router and should just be pointing everybody with static IPs at
the IP of the machine with the internet connection.

other option:
internet --- router --- all other machines
In this case everybody can just run dhcp and use whatever the router
tells them to use as gateway.

So which are you doing?

--
Len Sorensen
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