>> > I just got cable internet service from Comcast (formerly AT&T) and
>> > I'm
>> > using a Compaq CP-2E cable/DSL router. Right now I have 2 machines
>> > hooked up to the router: Win98 & Linux-Debian-Woody. The Win98
>> > machine works fine with this connection. I'm having trouble
>> > getting the Linux box set up.
>> > The router uses DHCP. Here's the router's default settings:
>> > LAN IP Address: 192.168.1.1
>> > Subnet Mask: 255.255.255.0
>> > DHCP start address: 192.168.1.11
>> > DHCP end address: 192.168.1.254
>> > The owner's manual says "...the default network IP address is
>> > 192.168.1.1. This IP address is also the default gateway and DNS
>> > server that local clients use to access the Internet..."
>> > My big question is this: Do I need to install the dhcp client on
>> > the
>> > linux box if it isn't hooked directly into the cable modem? I was
>> > thinking the router would take care of fetching an address from
>> > Comcast and I would configure computers on the network like they
>> > are hooked to a server (the router).
>> > When I type "ifconfig" it says eth0 has inet addr: 192.168.1.1,
>> > Bcast:
>> > 192.168.1.255, Mask: 255.255.255.0...
>> > I can ping 192.168.1.1. The router LED shows a connection after I
>> > boot up the linux box.
>> > When I type "route" it shows one line for "localnet ..."
>> > I'm a networking and linux newbie and I'm trying my best. I've
>> > read the cable-modem howto, the net howto, the dhcp mini howto and
>> > others, but it's all swimming around in my head right now.
>> > Any help would be greatly appreciated.
>> > Thanks,
>> > ~Steve Allgood
>> The Comcast ip address belongs to the router on the WAN side. This
>> address is not passed through to the computers.
>> If you use DHCP on the WAN side, the router will assign ip addresses
>> the computers in the private ip range 192.168.1.x. This is the
>> simplest way of doing it.
>> Linux comes complete with a DHCPCD which enables you to connect to
>> your router by simply telling linux to get the ip address
>> You do NOT assign parameters to the computers. The router will
>> assign ip addresses from its pool of private ip addresses, pass on
>> two or three DNS addresses from Comcast, pass its own LAN side ip
>> address of 192.168.1.1 as the gateway address and set the netmask
>> The whole idea of DHCP is that the client computer simply plugs in
>> and asks for the parameters and it is up to the router to supply
>> them. Makes life a lot simpler for the client and the system
>> The idea in an ip masquerading router (Network Address Translation
>> router) is that the computers use ip addresses that cannot be seen by
>> the internet. The computers don't care what public ip address is
>> assigned by the service providers, they exist on a private network,
>> not on the public network except through the router.
>> You can configure the router to use static ip addresses on the LAN
>> side but that would mean that you would have to manually set the
>> on each computer. Unnecessary drudgery.
> Weeeeheeeee!!! I'm writing this message to you from my Linux box!!!
> Thanks for your answers. They helped clear some things up. So the
> router is a dhcp client when it fetches a WAN address from Comcast?
> The it can be a dhcp server for my LAN?
> I was able to get it working by going to the dhcp settings of the
> router setup and using a feature called "Reserved IP table", "assigns
> a specific IP address to a PC on [my] local network based on its MAC
> address." So I used the Hardware Address that I got on the linux box
> from typing ifconfig" for eth0. Then I put that in the Reserved IP
> table with the address 192.168.1.200. Then I followed Linus's
> instructions and it worked! Now what's the best way to make it work
> every time I boot up? Do I just put the commands in a script and
> stick it in the /etc/rc2.d directory? (I boot into runlevel 2).
> Also, I did try installing the dhcp client with synaptic. It looks
> like there are 2 versions of it, something like: dhcp-client and
> dhcp3-client. There was a help file in the docs section that talked
> about which one to use depending on which kernel version you have. I
> tried installing both of them at separate times (after uninstalling
> the other) and couldn't get them to work. I wasn't quite sure what to
> do with them. Any suggestions?
OK.it looks like your router is still using DHCP on the LAN side to
assign ip addresses to any box connecting to it, but in respect of your
linux box you have told it to always assign ip address 192.168.1.200 to
it based on it having probed for a MAC address and having found that
the station requesting the ip address has that MAC address.
Of course this means that your windows box will never be assigned ip
address 192.168.1.200 as it has been reserved for a different MAC. You
could set your router to fix the address that it assigns to the windows
box as well.
So far as the computers are concerned, they are still talking to a
router that uses DHCP to assign ip addresses, but you have, following
linus's instructions, told your linux box to treat the static ip of
192.168.1.200 as its own.
At this point I am going to cop out and refer you to Chapter 25 of the
Linux Rute User's Tutorial and Exposition, a copy of which is online
But nobody configures current systems at this low level anymore. Most
distributions have a GUI configuration tool and most such tools are
accessed either through the desktop or from a command line.
In Mandrake, the desktop tool is called the Mandrake Control Center and
within it you can select Network and Internet then Connect which will
give you a menu driven set-up tool.
You can get to the same tool from a root command prompt in Mandrake by
I am sure that your distribution has the same utility. If so, it would
then be a matter of selecting the options to tell it that you are on a
lan and to get the ip address automatically using bootp/dhcp/zeroconf
and NOT entering parameters.