About the 2 macs and 1 linux on a LAN

John F. Kohler jkohler2 at earthlink.net
Sat Jul 15 13:09:19 PDT 2000



ME wrote:

> On Sat, 15 Jul 2000, John F. Kohler wrote:
>
> > I have tried the DHCP method of configuration, and the LinkSys router
> > handled it well for each of the macintoshes.  When I configured the
> > TCP/IP control panels of the macintoshes, there ware no entries needed
> > in the IP, Subnet mask or router boxes.
>
> When DHCP is used for Macs and newer windows (95 and later) systems, the
> areas where you would normally type in the information distributed by DHCP
> is often greyed-out or unavailable. Macs often say "Will be supplied by
> [DHCP/BOOTP] Server" Windows just leaves them greyed most of the time.
>
> What you describe above for the macs is expected.
>
> > After reading the posting from ME,  I set both macintoshes back to
> > "manual" configuration,
> > with the following addresses:
>
> If we assume you have a DHCP server somewhere on your network, and told it
> to assign addresses to your hosts, then this could be made to work ok.
>
> You have 2 common options for your linux box and the DHCP server.
>
> 1) You configure the DHCP server to offer a static IP address assignment
> for the Linux box's MAC address, and have the Linux box use a DHCP client
> for setting up its network. (How-tos exist for this procedure.) By
> "reserving" this IP address for your linux box on the DHCP server, it
> helps decrease the chance that another machine might be leased this IP
> address. (Actually, it should not be leased to another machine at all.)
> This allows you to use either a DHCP client, or manually assign the
> address without fear of two machines using the same IP address.
>
If I have a choice, I think I'd prefer manual, since I have a small 3 unit
home system.

>
>
> 2) You configure your DHCP server to only offer addresses to hosts that
> have MAC address entries in your DHCP server and have it act much like the
> older BOOTP systems.
>

I wonder if DHCP plays a role in the "manual" configuration, or if BOOTP
does.

>
> > router 192.168.1.1
> > macLC 192.168.1.2
> > iMac   192.168.1.3
> >
> > So I would think that the linux box could be
> >
> > 192.168.1.4
>
> Your logic, and direction is correct. Your linux box should be able to
> have that address.
>
> > But I don't know where to make that entry.
>
> Various ditros of Linux have their own utiities for setting networking
> information. You mentioned a few. Perhaps the other members of this list
> are sleeping. Their experience with these tools is much better than mine.
> I would assume you use Redhat. Confirming this may help others to help
> you.
>

Yes, I am now using Red Hat 6.2 which is reinstalling right now.

>
> > I found 2 Media Access Control addresses
> > in a query to the LinkSys router (by putting the router address in a
> > browser request)
> >  for LAN it was 00-20-78-C8-37-C8
> > for WAN it was 00-20-78-C8-37-C9
> >
> > The LinkSys router actually sends a "web page" through the LAN to either
> > of
> > the macintoshes, allowing me to choose DHCP, BOOTP or manual
> > and to observe the status of the line and ISP connections.
>
> > I think all I need to do is configure the Linux box for "manual"
> > operation.
> >
> > Incidentally, I cannot call the tool "ifconfig" from a terminal window
> > in linux,
> > bash tells me it was not found.
>
> This is often as a result of these command being contained in
> folders/directories not listed in your PATH defined in /etc/profile for
> bash.
>
> Compare and contrast the files:
> /etc/profiles
> ~root/.bashrc
> ~root/.bash_profile
>
> and note how the PATH env vars are different.
>

Thanks for the explanation.  I need to learn a lot more to work my way around

the pathes and heirarchical layout of Linux files.

>
> Often root will haver the paths "/usr/sbin" and "/sbin" added with
> "/usr/games" removed. Non root users are often not permitted to make
> changed to routes, or interfaces unless commands are Set UID root. (bad
> idea to do that.)
>

This is familiar to me.  Since learning how to set up PPP0, I have been able
to
invoke a modem connection with:
/sbin/ifup ppp0

>
> > I can start "netcfg" or "netconf" or "control-panel" from the terminal
> > window.
>
> When you are "administrator" or "root" and you run these applications,
> does it allow you to enter in your network information?

Yes, I can initiate any of the 3 tools, "netcfg" or "netconf" or
"control-panel" each of which allow me a graphic interface to configure the
values below.

>
> IP Address: 192.168.1.4
> Subnet Mask:255.255.255.0
> Gateway IP: 192.168.1.1
> Broadcast:  192.168.1.255
> DNS: ? (Whatever your mac/dhcp servers are set to use/hand out.)
>

In my case, I use Earthlink..... 207.217.126.81

>
> I have a theory, but it does not seem likely...
> If you linksys router is also acting as you DHCP server on your network,
> and is also doing your NAT(1 to many)/IP Masquerading) there is a *chance*
> that they have tried to implement some level of security.
> (NAT= Network Address Translation - IP Masquerading is but one kind of
> NAT)
>

It appears to me that I can enable or disable DHCP in the LinkSys box using
an access I can have from either macintosh.  Right now it is disabled, and I
have
assigned all values in the mac TCP/IP manually

>
> It is possible, but unlikely, that the router does not allow packets with
> source IP addresses not assigned from its DHCP server to pass through to
> the outside world. (This would not prevent your linux box from pinging
> other machines on the same collision domain like you Macs.)
>
> While we wait for someone else to help you through the use of the network
> configuration tools like "netcfg" "netconf" or the "network control panel"
> for linux, why not copy and past the results of the following:
>
> If someone is able to help you with one of the above tools, you may want
> to look at the results of these to see how the information you enter into
> those tools changes the data offered by running these.
>
> (as root:)
> # ifconfig eth0
> # ifconfig eth0:0
> # ifconfig eth0:1
> # ifconfig eth1
> # ifconfig eth2
>
> (Many or most of these may produce errors. Ignore the ones that produce
> errors, and only paste in the ones that have dumped data to your screen.
> If they *all* offer errors, then that is also helpful information.)
>

I did get an error
"delying eth0 initialization"
and some other stuff
Something about /lib/something and "tulip" (the driver for my ethernet card
from Kensington)

>
> Also as root run:
>
> # route -N
>
> There should be no serious issue in posting this information to this
> list, but if you do not feel confortable publishing this on this list, you
> can contact me directly on this part.
>
> -ME

ok

John




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