All those not working 3com cards

[Vaclav Hanzl]

Hey you all with blinking green leds, high and unpredictable packet
losses and totally non-working 3com cards,

Please kindly consider my following plea:

  Take it as a matter of fact that autonegotiation tends to be broken
  and hard-set the speed (10 or 100) and duplex (half or full) on both
  ends of your cable before you complain.

If it fixes your problem, you know you should complain about
autonegotiation.

If it does not, you can mention it and people like me will not bother
you with ever repeating suggestion to try this out.


3com cards can be hard-set using DOS setup utility which stores the
information to the on-board EEPROM. Setup utility is on a floppy which
came with your card. (If you do not have a DOS partition, put a floppy
to any DOS machine, type SYS A:, add COMMAND.COM on the floppy if your
SYS did not, boot your linux box from this floppy, insert 3com floppy
which came with the 3com card, run their configuration program named
something like 3C90XCFG.EXE.)

3com switches can be hard-set using telnet or www interface. The hard
part is to give a new switch its IP address to be able to access
it. You can do it using bootp. Connect working linux machine to the
switch, create file /etc/bootptab containing line like this:

swname:ha=0060978452B4:ip=123.45.67.89:sm=255.255.0.0

but containing the right values:

  instead of 'swname' put hostname of your switch
  instead of '0060978452B4' put MAC address written on your switch
  instead of '123.45.67.89' put IP of your switch
  instead of '255.255.0.0' put your subnet mask

Run /usr/sbin/bootpd, reset your switch, telnet to it and hardset its
IP to get there the second time. (Stop bootpd.) Hardset duplex and speed.


I know I am persuading you to give up part of your comfort - you have
to go through this again if you ever want to change the setup. But
beleive me that broken autonegotiation is an evil nuisance. Everything
might even seem to work, until you switch your machines off and would
like to switch them on again. You can find out that autonegotiation
work or not depending on the order in which you switch your equipment
on - if you ever find the right order again.

(Anyway, linux people have many reasons to hate 'automatic' things -
ever tried to force PnP bios to use interrupts you want it to use?)


Thanks for your attention if you are still reading. I hope this will
reduce a bit the number of messages on this list describing problems
unrelated to Donald Beckers great work. He is a scarce resource of the
linux community; let's bother him with caution.

Best Regards

Vaclav Hanzl