hp wrote:
> I took some old parts and pieces and rebuilt a 'working' pc, loaded
> windows XP pro. it fires up ok, but how do i get it online with a dsl
> connection? head is blocked right now and too tired to think well.
> no lights on the network ports of the motherboard.
> Could there be some steps in XP that I need to ensure was done right?
> Did get the mother board drivers all installed I thought.
>
> Do I need to get IE8 before hitting the MS update site?
>
> tanks
>
1) Verify BIOS settings. Check that the LAN is turned on. You don't
need the LAN boot rom enabled, unless you're doing something like
PXE boot over the net.
2) Step 1 is unnecessary if you check Device Manager while in
Windows, and it's present and the driver is installed. There
may be a couple tick boxes in the NIC device properties, such
as "allow the OS to turn off this device to save power" and
you can untick them so that the LAN is always on.
3) The NIC PHY (physical layer, the part that sends the 1's and
0's on the four or eight wire cable), has a negotiation function.
On some LAN chips, "no LEDs" equals 10BT mode, meaning the
PHY did not manage to communicate over the wire with another
Ethernet chip.
The PHY can also be prevented from negotiating, if the circuit is
jammed in reset. Of course, on a computer, the computer could not
boot if that was the case, so that is eliminated as a cause. But
when you know a LAN works, if the PHY lights don't come on, it's
either power is off or reset is jammed on.
4) Some LAN chips (perhaps Marvell brand), have a nice cable test
function. I have one motherboard, that can test the LAN interface
in the BIOS. The device on the other end of the link should be
powered down, if you're doing that kind of testing. The test is
basically an impedance test. It sends a pulse down each twisted pair,
and sees whether the pulse is hitting a termination resistor at the
end. If a pulse comes back, it can be right-side-up or upside-down,
and the pulse shape and time position, tells you where the cable
is broken, shorted, kinked etc. On other kinds of equipment, such
a test is called Time Domain Reflectometry or TDR. And a crude
version with 1 nanosecond resolution, is built into a few Marvell
gigabit chips. Some other LAN chips have a version of it now, but
they have even cruder time domain resolution.
LAN ports come with no LEDs, up to perhaps a couple LEDs. (Some embedded
systems can have as many as five LEDs, but that's because "we like LEDs" :-) )
It's likely if the port has a couple LEDs, that one LED will light
up for the most common 100BT or GbE negotiations with the other end.
You need a good cable, and a powered LAN box on the other end of the
link, to complete the negotiation sequence, which can be done
totally by the PHY hardware on each end. The OS gets to override
the negotiated value, once the OS is running, so if you "force" some
other LAN setting in the OS, eventually, it takes priority over the
hardware-negotiated value.
When the LAN RJ-45 connector has no LEDs, like on my $65 motherboard,
you've got a lot less feedback to go on.
*******
ADSL comes two ways. If you buy an ADSL modem today, chances are
it has a modem and router all in one. Even if there is only one RJ-45
for output, it can still have a router. One of the router functions,
is to convert PPPOE from the ISP, back into regular LAN packets.
"router mode"
X------ ADSL modem/router ------- Computer, thinks it's on a LAN
terminates PPPOE
I run my setup like this. The ADSL modem routing function is disabled,
and I use a separate router box. That's called "bridged mode".
"bridged mode"
X------ ADSL modem -------------- router ----------------- Computer, thinks
PPPOE terminates PPPOE it's on a LAN
So those are two options for the modern ADSL modem. I chose to do it
that way, because the web interface on my new ADSL modem, is horrible.
Router rules are loaded via a Telnet interface, and I'll be damned
if I'm heading back to the dark ages. The router rules in my
separate router box, are controlled by a web browser, and at
least those I can deal with easily. One of the things I do
in the router, is port forward IDENTD to a non-existent LAN-side
address, for stealth. That's about the only setting I need to make.
As far as I know, you can also do this. But because this limits you to
just the one computer, while my router has four wired ports, this
isn't as flexible. Not all operating systems, have the ability to
terminate PPPOE, and so this is more likely to work on a modern
computer. When I first got ADSL eons ago, I had to install a
software package to handle PPPOE. There was no router when I
set up my first ADSL. (And the ADSL modem only operated in
bridged mode and you had no choice in the matter.) I added a router
a few months later, when I got tired of the PPPOE software crashing.
The PPPOE software built into a modern OS, doesn't crash like that crap did.
"bridged mode"
X------ ADSL modem -------------- Computer, detects the PPPOE interface
PPPOE and has some software stack for it
I think I've tested the previous config on my WinXP box, as part of
my testing. So I did run it for about ten minutes, long enough
to set up the modem part, then once the router box was added and
I switched to the second diagram above, I've never been back
to the interface on the modem. Everything is controlled from
the router box (i.e. logging in to the ISP via PPP).
Paul
