About the 2 macs and 1 linux on a LAN

[John F. Kohler]

Mitchell Patenaude wrote:

> On Wed, Jul 19, 2000 at 11:11:32AM -0700, Mitchell Patenaude wrote:
> > P.S.  I haven't been following this in detail, but what I have gathered
> > is that you are trying to get a DEC tulip based NIC to be recognized
> > under RedHat.  The module loads, but doesn't ever work.  NIC works fine
> > under DOS.  Is that a fair summary?
>
> I went over to John's place after work last night. Here's what I found:
>

I am really grateful for Mitchell's visit.  I learned a lot about the nature
of the router, network practice, and troubleshooting.

I have been thinking about the parallel of a NIC working under DOS versus
working under Linux.    Kingston supplies 2 floppy disks with the NIC, one
each
for DOS and Macintosh.  I had an emergency Windows95 boot disk  and we tried
the
Kingston program "Q-Start" on the pc to learn if the card was visible to the
system.

It was.  Four tests were performed, and the Media Access Control address was
displayed as well as the hex address 6000 of the ethernet setting.

What I am wondering is whether or not Q-Start is a fair test for what tulip
requires
of the Kingston card in terms of duplex/ half duplex, timing of pulses, etc?

John

>
> Hard coding the IRQ in the conf.modules wasn't a good idea, so I removed
> that, and the module would load properly, and we got link light, etc.
> However, he's still not getting ping from the other machines on his
> home network.
>
> We verfied the cable/network port by swapping cables with working machine.
> So it's definately something about the card.
>
> The best clues I could find were:
>
> The lights on the LinkSys router showed that we had link, but it also
> showed 10 rather than 100, (the 100 light wasn't lit like it was for
> the two macs he had connected.)
>
> When I did a flood ping, a very few packets would get through.  There were
> about 5% showing up as errors, 1-2% showing up okay (though with ping
> times ranging from 2ms up to 47seconds (47000 ms).
>
> Tcpdump showed that arp was working, but only sporadically.
>
> tcpdump didn't find the echo_request packets from the other machines on
> the network.
>
> I got the tulip_diag and mii_diag programs, and they showed that the card
> thought it was running in MII 100 with full duplex.  (Interesting that
> the router didn't show the 100 light). I thought that the FD might be
> the problem, so I hard coded it to half duplex using the options=13 line
> in the /etc/conf.modules, but that didn't help, and may have hurt.
>
> I'm thinking it's probably an inabililty of the kingston (tulip) card
> to handshake properly with the router.  I would suspect a bad cable,
> but when we pulled it out from the back of the linux box and plugged it
> into his mac it worked fine.  When we plugged the cable from the working
> mac into the tulip card, it failed on the linux box, so the trouble is
> definately in the case.  I would suspect that the card itself it bad,
> but John says it was working fine at the install fest a few weeks back.
>
> Does anybody else have any things to try that we haven't already?
>
>   -- Mitch