RE: [SLUG] networking

From: Ken Elliott (kelliott4@tampabay.rr.com)
Date: Sat Jul 24 2004 - 20:23:28 EDT


Ok, let's see if I've got this, starting from the outside, working toward
the Mac. You have an Internet connection to a wireless router in a front
room. The router does not have any computers connected to it via wire, and
talks wireless to the Linux box in the back room. There are no other
wireless machines. The Linux box is wired to the Mac (also in the back
room), perhaps via a hub. You'd like to be able to hook up several wired
Macs to the hub.

If that's correct, here is how I believe you need to configure things. You
will actually have two networks - the wired network between the D-Link
router and the Linux box, and a second wired network in the back room. The
Linux box has a network interface on each network, and will route packets
between the two.

First, setup the wireless network:
The D-Link router will not get an IP address from any DHCP server (to the
best of my knowledge). It has to be a fixed address, or be the only DHCP
server on that network. I would use a fixed address on the Linux wireless
card and turn off DHCP on the router. For security, you could have it
accept only the Linux box's wireless hardware address. Once this is done,
check to see if the Linux box has Internet access. Let's assume your router
uses 192.168.1.x for that subnet. The Linux wireless interface should be
fixed at, say, 192.168.1.10.

Now setup the Wired Network:
Setup DHCP on the Linux box with the address range 10.0.0.x to the wired
interface only. So a Mac DHCP request would be answered by the Linux box,
which would supply the address. This setup means you have two different
networks, using the Linux box as a router between them. The Macs would sit
on the 10.0.0.x network and see the Linux box as the router. The Linux box
MUST have the wireless card on a different subnet or it won't be able to
understand what to do.

You most likely don't need a DNS server. Set the Linux DHCP to point to
your ISP's DNS servers. When the Mac try's to look up a web page, it's
request goes to the Linux box, routes to the D-Link, routes to the ISP's
DNS. Should work.

When a packet from the Mac (addressed to the Internet) hits the Linux box,
it opens the packet and sees a destination address that is NOT 10.0.0.x and
automagicly passes it to the 192.168.1.x network, addressed to the D-Link
Router. The same thing happens at the D-Link router to the Internet. If
both Linux network interfaces have the same network subnet, it cannot tell
what to do.

If you don't intend to use the Linux box for anything else, you could take
the easy way out and install SmoothWall. That would give you a very robust
firewall/router that's easy to setup.
http://www.smoothwall.org/

I'm experienced in networks, but new to Linux (using SuSE 9.0 and 9.1).
Smarter folks will step in and suggest ways to configure your Linux box to
accomplish this. Mine is down right now getting a badly needed
Motherboard/processor upgrade.

Ken Elliott

=====================
-----Original Message-----
From: slug@nks.net [mailto:slug@nks.net] On Behalf Of A2L1
Sent: Saturday, July 24, 2004 6:02 PM
To: slug@nks.net
Subject: Re: [SLUG] networking

I am not the best at clarification , let me try to clearly explain. Although
the dual dhcp thing might be the problem.
OK here it goes. The linux box has its internet conection by PCI wireless
card so the internet to the back room is only by wireless. So that I dont
have to buy multiple wireless cards I figured to make use of what I have. I
have the linux box up
24/7 and it has a built in nic so I figured to use that as a "server" to the
D-link router(which is also just laying around. The D-Link is set as a dhcp
server. I have multiple macs and a few other tower units (windows and
linux). If the D-Link is hooked up I can then just plug and unplug as I need
the other units to be online.
Now if there is a problem with the linux box being a dhcp server to the
router which in turn is a dhcp server then I guess the linux box would have
to still be a server to the router but using a static?
Networking is not even close to something I comprehend fully and I get just
more confused as I read more, mostly the terminolgy is difficult to put in
context. In plain and simple terminolgy here is what I would like to do !.
get the linux box to act as a server to provide internet to the
router/firewall 2. Have the router/firewall act as a server so that I may
plug in different units that I am testing or working on.
3.I would like to use the existing hardware that I have. i have plenty of
nic's and a ton of cable, two different router/firewalls/.
The problem with wireless with the mac is the macs use 40 bit wep and wont
hook up to the 64 bit wep on the wireless so in order to get internet access
for the macs I have to either have a cable(rj45) connection or have to use
mac
airport(expensive) which I do not want to buy.
With everything that can be done with linux there has to be a way to use the
linux box with its wireless internet access to provide internet access to
the other units in the room, I just dont have a clue on how.
For now I will try to have the D-Link issue static IPs and see if I can
connect, but I would prefer a dhcp because it would be easier when I hook up
other boxes.
Thanks for the input, I'm off to try.
A J

On Saturday 24 July 2004 16:19, Ken Elliott wrote:
> >>I installed and initiated both dhcp and dns servers
> >>
> >>The D-Link shows a Wlan signal and when I connect a caple to it and
> >>to the
>
> mac it also shows a connection.
>
> Do you have DHCP turned OFF on the D-Link router? You can't have two
> DHCP servers on the same network segment.
> So, if you have the Mac and Linux box both plugged into the router you
> must either use the router's DHCP server, _OR_ the Linux DHCP server,
> but never both. Now, if you have two network cards in the Linux box,
> one going to the router, one going to the Mac, that's different.
>
> Why are you going to the trouble of using a DNS server for just 2
> computers? It that's all there are, you could simply create a hosts
> file on each machine, containing the hostname and IP address of the
> other, and either use fixed IP addresses, or configure your router to
> assign a known IP address based on the NIC hardware address.
>
> I don't think I understand everything you're trying to do, so more
> information will help.
>
> Smarter more Linux-savvy guys will chip in soon.
>
>
> Ken Elliott
>
> =====================
> -----Original Message-----
> From: slug@nks.net [mailto:slug@nks.net] On Behalf Of A2L1
> Sent: Saturday, July 24, 2004 3:18 PM
> To: slug@nks.net
> Subject: [SLUG] networking
>
> Hello,
> Things were progressing nicely, got the antenna up and signal strenght
> is up on the wireless and that is all working well.
> The problem I am having is getting SuSE 9.1 pro to act as a dhcp
> server. I installed and initiated both dhcp and dns servers and they
> are up and running according to yast. I connected a cable to the
> onboard nic ( which is designated as eth0 by the bo and the other end
> to a D-Link router/firewall. The D-Link shows a Wlan signal and when I
> connect a caple to it and to the mac it also shows a connection. The
> mac shows an Ip and subnet but cant connect to the net. i cannot ping
> the linux box from the mac. I can access the D-Link from the mac and
> access all the settings(they all seem right---dhcp).
> I am assuming that the SuSE box is not sending a dhcp to the D-Link
> and I dont know what to do next. Has anyone set a SuSe
> 9.1 pro box as a dhcp server and would it be possible to get a copy of
> the /etc/sysconfig/dhcpd. I assume that is what needs modifying? Any
> help is appreciated.
> Thanks,
> A J
>
>
>
>
>
>
> --
> Feel safe and confident,there were no M$ products used in the
>creation of this email, only virus-free and rock solid LINUX!
> Registered LINUX user #191255
> -----------------------------------------------------------
>------------ This list is provided as an unmoderated internet service
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> Views and opinions expressed in messages posted are those of the
>author and do not necessarily reflect the official policy or position
>of NKS or any of its employees.
>
> -----------------------------------------------------------
>------------ This list is provided as an unmoderated internet service
>by Networked Knowledge Systems (NKS).
> Views and opinions expressed in messages posted are those of the
>author and do not necessarily reflect the official policy or position
>of NKS or any of its employees.

--
Feel safe and confident,there were no M$ products used in the creation of
this email, only virus-free and rock solid LINUX!
Registered LINUX user #191255
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This list is provided as an unmoderated internet service by Networked
Knowledge Systems (NKS).  Views and opinions expressed in messages posted
are those of the author and do not necessarily reflect the official policy
or position of NKS or any of its employees.

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