Re: Local network detection problem


Subject: Re: Local network detection problem
From: nathan r. hruby (nhruby@arches.uga.edu)
Date: Tue Dec 18 2001 - 08:38:35 MST


On Tue, 18 Dec 2001, Geert Janssens wrote:

>
> My G3 is configured as a router (or gateway ?) for my lan. The lan
> consists of my G3 and 2 windows PC's connected via a 100 Mbs hub.
>
> My G3 has 2 ethernet interfaces:
> - the built-in 10Mbps BMAC (which the kernel assigns to eth1)
> - an Assante 10/100 Mbps PCI card (which the kernel assigns to eth0)
> The kernel detects this card as:
> eth0: Lite-On PNIC-II rev 37 at 0xcd861000, 00:00:94:C7:89:FE, IRQ 24.
>
> During boot, a message appears that eth0 initialization was successful.
> However, trying to ping one of the PC's on the lan results in a host not
> found.
>
> I read through the startup messages (messages) where this error line
> appears:
> eth0: Autonegotiation failed, using 10baseT, link beat status 10cc
>
> But that of course is wrong, my lan works at 100Mbps.
>
> If I now manually ifdown eth0; ifup eth0' the problem is resolved, and
> the lan works.
>
> So I have a work around, but I would like to understand what goes wrong
> and why, so I can have a fully working system from boot, without doing
> work arounds.
>

There might be several issue going on here:

- Evidently the interface can't autodetect the media type. You can force
  the card to use one media type over the other by adding it's flag into
  /etc/conf.modules. I don't remember the options off the top of my head
  and they are different for each driver. Find the docs for the Asante
  Driver and see if it offers this option. You may be able to fix this by
  simply using a different cable, as a bad / cheap cable can cause
  auto-negotaition issues. (Assuming that you hub is 10/100 and not just
  100 only :) I have several very old Asante MicroPrint Appletalk ->
  Localtalk print servers that refuse to auto-negoatiate with my new
  switches. It takes them a few power-cycles to finally do it, so
  auto-negoatiantion doesn't always work.

- I assume that you want your linux box to be a IP MASQ box. Read up on
  either the ipmasq / ipchans code or the iptables code. Both will do
  what you want, iptable sis newer and for the 2.4 and later kernel
  series, while ipchains is availible for both 2.2.x and 2.4.x
  http://netfilter.samba.org/unreliable-guides/ should help you with
  iptables. Use google for any ipchains questions you may have, there are
  *tons* of HOWTO's and articles out there.
  (http://netfilter.samba.org/ipchains/HOWTO.html is one)

-n

-- 
......
nathan hruby - nhruby@arches.uga.edu
computer support specialist
department of drama and theatre
http://www.drama.uga.edu/
......



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