crossover cables, dec 21041 nic, fbsd vs nt

[Olaf Hoyer]

On Sat, 7 Aug 2004, Gary Aitken wrote:

>
> While waiting for a new hub to arrive, I decided to jury-rig
> a workstation to the firewall freebsd box. (4.10)
> Using a cat5 crossover cable, I connected the nic on an NT
> box to the NIC on the freebsd box; each of these normally
> goes to the hub for the internal network.
>
> ping... nada
>
> So I swapped the network cards individually with the card
> serving the dsl modem; they all work.
>
> So I used the crossover cable to connect the NT box to
> another NT box on the internal network.  ping...reply
>
> The nic in question is an old smc 3c509b-combo card
> supporting 10baseT UTP, AUI, and BNC.


Hi!

Well, 509b comes to mind as also a product from 3Com...

>
> ifconfig de0 shows:
> 	media: Ethernet autoselect (10base2/BNC)
> 	status: active
>
> The green light (indicating a live connection?) is on on both nics.
>
> Manually configuring the nic media type to 10BaseT/UTP made it work.

So it is a PCI card, supporting 3 connectors. I had similar hassle with
some 3com 509 ISA cards, where it was a pain to set the correct
connector type, also regarding the correct duplex setting (full/half)


>
> What's different about a hub environment that allows the system
> to automagically determine the media type?

a hub is always half-duplex (a switch is full or half), and I also
experienced some old 21040 cards that needed to be fully brought up with
an IP to detect their connection status.

I could guess that the NT box has some problems with the autoneg on
their side, try setting it in the NT driver to a fixed speed/duplex
setting.


>
> NT seems to have no problem, although it may be the driver is
> just defaulting to the right choice in one case and the wrong
> one, or none, in another.
>

see above, set the speed/duplex manually on both sides.



HTH
Olaf
-- 
Olaf Hoyer        ohoyer at gaff.hhhr.ision.net
Fuerchterliche Erlebniss geben zu raten,
ob der, welcher sie erlebt, nicht etwas Fuerchterliches ist.
(Nietzsche, Jenseits von Gut und Boese)