[vox-tech] 2-nics question

[Dave Margolis]

just got done reading about the nocat stuff.  a very intereting project
(great name too).  what those guys are doing is kind of the opposite of
my goal - which i just got working by the way!

now that i've got this working it would be simple enough to switch the
roles of the two nics to achieve a very low cost alternative to a store
bought wireless router or access point.  so it's really not that far off
from the nocat stuff.

you and jeff both suggested i might not need a crossover cable.  that was
correct; both of my nics agreed to play nice with the standard cable.
we'll see if the gamecube's nic is as agreeable.  if not, a
crossover cable is cheap enough.

man, this was such a fun little experiment...  and what a great use of
an otherwise useless POS laptop with a cracked case and no battery.

i've still got some learning to do as far as iptables goes, but what i've
got so far seems to be working for my purposes.

Thanks again (and Jeff too).

On Sat, 13 Dec 2003, ME wrote:

> Dave Margolis said:
> > I want to put an ancient laptop to use as a wireless bridge.  My Gamecube
> > sits in a room that I can't get ethernet to without a lot of effort.
> > I could buy the Linksys _gaming adapter_ or any of several similar
> > devices,
> > but I figured this would be worthwhile experiment and I can save some
> > cash.
>
> I do not know about the gamecube side of things, but if I replace gamecube
> with "generic computer" then what you describe is possible.
>
> This may be useful as a resource. http://nocat.net/ This is a group of
> people who have been working on making wireless access points out of
> cheap/slow hardware. Their purpose is for creating a community-services
> and sourced Internet access for others. However, their project can also be
> used to helpyou with the filtering/NAT and other parts.
>
> They have also had discussion on their lists for creating wireless routers
> (wireless to wireless kinds of "range extenders" for network access.
>
> > Here is what I have:
> >
> > P-I 100 / 40MB ram / 2GB HD -  Toshiba Laptop
> > Slackware 9.1 slim install < 200MB for base install and some networking
>
> That can be a NAT/DHCP box easily enough.
>
> > 1 wired pcmica nic (dhcp server to the gamecube, and perhaps other
> > devices if I get a hub or switch) - eth1
> > 1 wireless pcmcia nic (dhcp client to my wireless router) - eth0
> >
> >
> > I just installed the OS and everything is working.  The wireless nic is
> > talking to the router and the outside world.  I configured the wired card
> > as 192.168.1.1 (my _normal_ home network is 192.168.0.0).
> >
> > Here is where I don't know what to do next.  I've got DHCP installed, but
> > I've never configured it before.  Assuming I can get DHCP working through
> > that nic, what software do I need or what configuration is required to
> > _pass_ the internet through this machine.  I know I'm showing my
> > networking ignorance here, but I've always used a hardware router...
>
> This is not clear. If the laptop will be a dhcp server, then you can check
> out the free dhcp server from ISC. You configure it to server addresses in
> a subnet. (In this case, the subnet to serve would be 192.168.1.0/24)
>
> It is possible to have a single dhcp server on a network and use DHCHP
> relay across subnets, but that will raise the bar on education
> requirements when compared to a new dhcp server.
>
> Next, you will need to setup some kind of NAT or masquerading of IP
> address information. I expect this will be necessary as your commercial
> NAT/Masquerading/Router/Wireless unit is probably configured to only NAT
> for the private network for which it is subnetted.
>
> Depending upon the NAT/Masquerading/Router/Wireless unit, you may be able
> to have the laptop just act a a router (without NAT/Masquerading) but this
> will require support on the NAT/Masquerading/Router/Wireless unit for
> routing so that it will know where to "route" packets for the new subnet
> based on destination address.
>
> One advantage to simple Masquerading/NAT is that it is modular; you only
> need to configure the box doing the NAT and do not need support from the
> gateway that is used by the box being configured.
>
> > For this part, I'm sure I can
> > RTFM, but if anybody can give me a quick 1,2,3 or point me in the
> > direction
> > of good reading material, that would be great.
>
> There are NAT/Masquerading how to on the linux documentation project site.
> These cover setting up NAT/Masq as well as DHCP server setup. These HOWTO
> are "the quick 1, 2, 3." Certainly it is possible to have a shorter list
> of steps customized on a per user, per requirement  case, but such
> documents have little use for the general population. The HowTo are good
> generic docs which cover most generic tasks people desire to accomplish.
>
> > The part I'm really unclear on is this:  do I need a crossover cable to
> > talk to the Gamecube (or whatever dhcp client)?  If I plug a hub into the
> > wired nic, does that require a crossover cable, or a regular one?
>
> Some newer NIC can auto-sense and auto-flip to match the devices to which
> they are connected. (If the device is a hub, then connection is "normal"
> while connections directly to other devices can cause the NIC to switch Rx
> and Tx to also have that work.)
>
> > I haven't bought the gamecube network adapter yet, and I wasn't planning
> > on doing so until I proved this would work (I can always test with another
> > laptop).
>
> I do not know about the gamecube side of things, but I know what you
> describe is possible for other devices. I have setup my laptop as a
> wireless to wired-network router back when wireless was new and some
> people wanted network access shared.
>
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