trouble getting RH9 to work with cable modem

I'm trying to get RH9 to work with a cable modem. i can't get an ip address
with dhcp. i've followed the instructions at:

http://www.redhat.com/mirrors/LDP/HO...iguration.html

these are fairly obvious and should work for any dhcp environment. it works
when i use a router/NAT as the dhcp server but not when i try to connect
directly to the cable modem. the same machine will receive an ip address
from the cable modem using windows xp.what could be the problem? i ran
dhclient directly and it tells me its sending DHCPDISCOVER messages but
receives no DHCPOFFER messages. any help is greatly appreciated.


--
Gary Roach
ADB Services

On Wed, 20 Oct 2004 17:23:56 -0400, Gary Roach wrote:
> I'm trying to get RH9 to work with a cable modem. i can't get an ip address
> with dhcp. i've followed the instructions at:
>
> http://www.redhat.com/mirrors/LDP/HO...iguration.html
>
> these are fairly obvious and should work for any dhcp environment. it works
> when i use a router/NAT as the dhcp server but not when i try to connect
> directly to the cable modem.

When you get a lease on your XP box, try clicking up _cmd_ and doing a
ipconfig /release

Anytime you change the device connected to a cable modem, power off
the cable modem for at least 15 seconds by your watch.

Gary Roach wrote:
> I'm trying to get RH9 to work with a cable modem. i can't get an ip address
> with dhcp. i've followed the instructions at:
>
> http://www.redhat.com/mirrors/LDP/HO...iguration.html
>
> these are fairly obvious and should work for any dhcp environment. it works
> when i use a router/NAT as the dhcp server but not when i try to connect
> directly to the cable modem. the same machine will receive an ip address
> from the cable modem using windows xp.what could be the problem? i ran
> dhclient directly and it tells me its sending DHCPDISCOVER messages but
> receives no DHCPOFFER messages. any help is greatly appreciated.
>
>
My guess... 1) is the Nic card working ? (and seen by Linux)
2) is the cable modem all green ? (working)

If the Nic is ok, then try unplugging power from the cable modem &
as all its green lights come on run dhclient. WAIT for reply !
If the above does not work you have a cable modem or line problem.

Kahn

> Gary Roach wrote:
> > I'm trying to get RH9 to work with a cable modem. i can't get an ip address
> > with dhcp. i've followed the instructions at:
>> it works
> > when i use a router/NAT as the dhcp server but not when i try to connect
> > directly to the cable modem. the same machine will receive an ip address
> > from the cable modem using windows xp.what could be the problem?

The most likely reason for it working under WinXP but not directly, is
that WinXP has a PPoE (or PPoA) driver installed (that seems to the
default for most cableco supplied setups), but you do not have an
equivalent in Linux, so it will not work directly connected to the
'cable modem'. Most routers are set up to do that in hardware so you
should be able to get it working.

Possibilities: a) the NIC is not set up properly under Linux...it is
not talking to the router.
If you can use Mozilla to access the router's config page (using
http://192.168.1.1 or whatever the default address is) then the NIC
is working.

b) the NIC is set to a *static* address in Linux but the address is
outside the range that the router works in. (The NIC is set to
10.0.0.xx while the router is 192.168.1.xx...)

The fact that it works under WinXP proves that the hardware is
capable, but does not help actually in tracking down the config
errors. In config terms, these might as well be 2 completely different
boxes.

For tracking down errors, the best method is to set the computer to a
static IP. If it can then 'see' the router, you know that thje
config/hardware combo is set up correctly. THEN change it to DHCP if
you want. If you can see the router, but can't get any further, start
by using another computer (laptop) and see if you can ping the static
address of the first box *through* the router. This also helps for
checking your cabling when you are re-arranging things. Then go back
and check that you have the gateway and DNS IP addresses properly set
up... Then power cycle the router and cable-modem to refresh things.

Geoff

I think your idea about PPPoE is the most likely problem. I'm looking for
info on this. I might try installing Roaring Penguin.

thanks


"R. G. Newbury" <(E-Mail Removed)> wrote in message
news:JcldVHe8EppF-pn2-S122dwCIejJB@Tor2...
>> Gary Roach wrote:
>> > I'm trying to get RH9 to work with a cable modem. i can't get an ip
>> > address
>> > with dhcp. i've followed the instructions at:
>>> it works
>> > when i use a router/NAT as the dhcp server but not when i try to
>> > connect
>> > directly to the cable modem. the same machine will receive an ip
>> > address
>> > from the cable modem using windows xp.what could be the problem?
>
> The most likely reason for it working under WinXP but not directly, is
> that WinXP has a PPoE (or PPoA) driver installed (that seems to the
> default for most cableco supplied setups), but you do not have an
> equivalent in Linux, so it will not work directly connected to the
> 'cable modem'. Most routers are set up to do that in hardware so you
> should be able to get it working.
>
> Possibilities: a) the NIC is not set up properly under Linux...it is
> not talking to the router.
> If you can use Mozilla to access the router's config page (using
> http://192.168.1.1 or whatever the default address is) then the NIC
> is working.
>
> b) the NIC is set to a *static* address in Linux but the address is
> outside the range that the router works in. (The NIC is set to
> 10.0.0.xx while the router is 192.168.1.xx...)
>
> The fact that it works under WinXP proves that the hardware is
> capable, but does not help actually in tracking down the config
> errors. In config terms, these might as well be 2 completely different
> boxes.
>
> For tracking down errors, the best method is to set the computer to a
> static IP. If it can then 'see' the router, you know that thje
> config/hardware combo is set up correctly. THEN change it to DHCP if
> you want. If you can see the router, but can't get any further, start
> by using another computer (laptop) and see if you can ping the static
> address of the first box *through* the router. This also helps for
> checking your cabling when you are re-arranging things. Then go back
> and check that you have the gateway and DNS IP addresses properly set
> up... Then power cycle the router and cable-modem to refresh things.
>
> Geoff
>
>

"Gary Roach" <(E-Mail Removed)> wrote in message
news:LKRdd.2688$(E-Mail Removed)...
> I think your idea about PPPoE is the most likely problem. I'm looking for
> info on this. I might try installing Roaring Penguin.
>
> thanks
<snip>

I've never heard of PPPoE on a cable modem. The only place I've seen PPPeE
are in DSL/ADSL modems.

Randy

On Thu, 21 Oct 2004 17:28:03 UTC, "Randy McLaughlin"
<(E-Mail Removed)> wrote:

> "Gary Roach" <(E-Mail Removed)> wrote in message
> news:LKRdd.2688$(E-Mail Removed)...
> > I think your idea about PPPoE is the most likely problem. I'm looking for
> > info on this. I might try installing Roaring Penguin.
> >
> > thanks
> <snip>
>
> I've never heard of PPPoE on a cable modem. The only place I've seen PPPeE
> are in DSL/ADSL modems.

I've never *heard* of it either. Then again, I've never heard that
cable modems *don't* use PPoE... I have no idea. I do know that most
cableco's and DSL providers, give you their own CD of software, which
is always wincrap and nothing more. What is actually included,
generally the tech support people do NOT know...

And there is a good possibility that there is some specialized driver
needed to make the thing work.....AND it is most likely specific to
the cableco.... they seem to delight in being 'unique'... probably in
an attempt to defeat program theft....


Geoff

R. G. Newbury wrote:

> I've never heard of it either. Then again, I've never heard that
> cable modems don't use PPoE... I have no idea.

Don't get out much, do ya? ;-)

--

(This space intentionally left blank)

"Gary Roach" <(E-Mail Removed)> wrote in message news:<oHAdd.2620$(E-Mail Removed)>...
> I'm trying to get RH9 to work with a cable modem. i can't get an ip address
> with dhcp. i've followed the instructions at:
>
> http://www.redhat.com/mirrors/LDP/HO...iguration.html
>
> these are fairly obvious and should work for any dhcp environment. it works
> when i use a router/NAT as the dhcp server but not when i try to connect
> directly to the cable modem. the same machine will receive an ip address
> from the cable modem using windows xp.what could be the problem? i ran
> dhclient directly and it tells me its sending DHCPDISCOVER messages but
> receives no DHCPOFFER messages. any help is greatly appreciated.

Most cable companies that I am aware of use mac address registration
to hand out IPs via DHCP, meaning they wnat to know the mac address of
your machine.

If you've run XP directly connected to the cable modem maybe they have
sone something to spoof the mac address on the XP side. Check the mac
address as reported in linux ifconfig against XP. If the XP mac is
different you aren't going to get an IP directly connected in linux
unless you spoof the mac address as well.

On Sun, 24 Oct 2004 22:26:33 UTC, James Knott <(E-Mail Removed)>
wrote:

> R. G. Newbury wrote:
>
> > I've never heard of it either. Then again, I've never heard that
> > cable modems don't use PPoE... I have no idea.
>
> Don't get out much, do ya? ;-)

Naaah.... the navel-gazing takes a fair bit o' time. And then there's
carding the lint....

BTW, that tag-line that said "(This space intentionally left
blank)"...That was your boss, talking about the space between your
ears, right???

<VBG>

Geoff