[YLUG] Interesting Networking Problem

[Njal Munro]

Thanks for the replies thus far, i have tried a few things namly this

ifconfig eth0 down
ifconfig eth1 down
brctl addbr br0
brctl addif br0 eth0
brctl addif br0 eth1
dhclient br0

This just seemed to disconnect me and not connect again, however i shall
try again, also i beleive i mentioned the laptop is running dapper
(unstable ubuntu) due to the fact i need the bcm43xx driver and it's
only in kerenl 2.6.15 or higher. I assume that br0 does not require eth0
or eth1 to be active while br0 is active? Also since i couldn't find a
brctl in the ubuntu repo's i checkinstalled it, and it seemed to work.

I can confirm that br0 was created but when i switch to the interface it
just registers that it's disconnected. This is while eth0 and eth1 are
also down, since i am assuming eth0 and eth1 need to be down while br0
is up.

Currently I am only using eth0 for wireless, i am discocnnected from
eth1 and a quick brctl show returned this:

njal at serenity:~$ brctl show
bridge name     bridge id               STP enabled     interfaces

Having only learned about the existance of brctl this morning, I may be
mistaken, however it seems to me, there should be something there, no?
Running the command as brctl show br0 and as sudo return the same
values, is this a problem?

The NAT route (no pun intended) i tried before, i beleive this was how
the network was working before, but as i said after a kernel upgrade i
rebooted and the routing tables(?) were reset.

There would be an easy solution to this problem, does anyone know a
wireless card that'll work in both fedora or ubuntu, preferably nativly,
because i could just set up the desktop as it is.

Eventually the idea is to extend the server beyond my room to be
acccessable by the entire house, so a LAN is going to be required at
some point too, but i wanna take this one step at a time.

Many thanks again.
Neil Munro

On Mon, 2006-05-08 at 01:32 +0100, Matthew Bloch wrote:
> On Monday 08 May 2006 00:58, Njal Munro wrote:
> [snip]
> > This laptop is asigned a ip from a DHCP wireless router, i cannot change
> > the fact it's assigned by DHCP, it's not my router, it's a uni house.
> > However once the laptop is assigned it's IP on wireless interfact (eth0)
> > it should share it's connection with the Desktop via an ethernet cable
> > (eth1) the laptop's eth1 connects to the desktop's ethernet (eth0) and
> > both SHOULD be on the internet.
> >
> > The laptop's eth1 port is assigned the static IP 192.168.0.1, the
> > desktop's eth0 is assigned 192.168.0.2 it's gateway is assigned as the
> > laptop's IP, and the DNS info was copied from my laptop to my desktop
> > propery, now the desktop run's fedora 5.
> 
> Hi Neil, this sounds like you're asking for trouble assigning IP ranges in the 
> same range to different interfaces!  If it worked before I wouldn't like to 
> guess how :)
> 
> I'd suggest in this situation turning the laptop's eth0 and eth1 into a 
> single "bridge" interface.  You didn't mention what distro the laptop was 
> running but from a standing start where the laptop hasn't got either 
> interface configured, this ought to work:
> 
> ifconfig eth0 down
> ifconfig eth1 down
> brctl addbr br0
> brctl addif br0 eth0
> brctl addif br0 eth1
> 
> The laptop can then set up interface br0 as normal (e.g. run "dhclient br0") 
> which acts exactly the same as eth0 did.
> 
> The desktop can then have a simple dhcp configuration as well, and get its IP 
> direct from the router rather than have the laptop work as a router.
> 
> Let me know if you need any more of a hand with this -- as I said I can't 
> really guess how it might have used to work but it doesn't sound like an 
> entirely healty IP configuration.  This way your laptop acts as a simple 
> wireless to ethernet bridge, and the desktop doesn't need to be aware of its 
> presence.
>