About the 2 macs and 1 linux on a LAN

[ME]

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.

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.


> 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.

> 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.

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.)

> 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?
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.)


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 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.)


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