[TriLUG] eth0 flaky problem

[Lisa Lorenzin]

> 'service network restart' should restart your ethernet interface without 
> rebooting.

you'd think, wouldn't you? :)  this is what started me looking for 
redhat-config-network in the first place...  (and rebooting this laptop 
about a dozen times over lunch.)

i have a xircom ethernet/modem pcmcia nic (xircom realport cardbus
ethernet 10/100+modem 56, RBEM56G-100); there's a xircom_cb entry in 
lsmod, so i'm assuming that's what it's using for a driver.

my original goal was to be able to stop the card (using ifdown eth0 or
service network stop, whichever), reconfigure it to either use dhcp or the
static IP of my choice, restart the card (using ifup eth0 or service
network start, whichever), and have it work.

now i'd just settle for being able to successfully stop and restart the
card, even without a reconfig in between.  but so far, the only way to
consistently do that is to reboot.

i started out running dhcp[1] - the interface comes up on boot, and can
ping the gateway.  but once the system is booted, the interface generally
fails to restart[2] without a reboot.  neither ifdown/ifup nor service
network restart works.  one single time, when it was booted with the
ethernet cable connected and ONBOOT=yes, i was able to successfully
restart the interface with service network restart and ping - but only
once, and i wasn't able to replicate it.

so i switched to a static IP[3], thinking that linux might be having 
issues talking to our (NetID) dhcp server.  things got even More Fun(tm).    

it boots, eth0 comes up and can ping, i run service network restart - and
i get "destination unreachable" from the interface.  out of about 8 tries,
there were two instances where it actually worked correctly - ie, i could
ping after a restart - but then when i ran service network restart a
second time, i started getting unreachable again.  ARGH!

if it was failing every single time, i'd think there was something being
done by/to the network interface on boot that isn't being done by/to it
via service network restart or ifdown/ifup - but i'm not sure, because
*very* infrequently, it Does The Right Thing.  the only thing i can think
of that might give these symptoms is a duplex problem - but i don't have
any way to change, or even see, the speed and duplex on eth0.  i've walked
the switch port through all 5 settings, restarting the network service
between each change, but to no avail - and the port isn't showing any
errors, either.

(i am not having a Good Linux Day(tm).  it's particularly irritating
because this is one of two identical test laptops, the other one is
running win2k, and i specifically put linux on this one to make it easier
/ more useful for testing.  i really don't want to have to go dig
up an m$ cd...  sigh.  somewhere out there, i can hear bill gates
laughing.)

							lisa


ps.  while i was testing this, i ran across yet another weirdness.  in all
cases (static/dhcp, ONBOOT=yes/no, ethernet cable connected/disconnected)  
the ethernet card comes up on boot.  it's like it's ignoring the ONBOOT
value in ifcfg-eth0.  the weird thing is, "service network restart" will
attempt to start it, or not attempt to start it, based on that value.  
don't know if it's related, or just another odd data point...


1: /etc/sysconfig/network-scripts/ifcfg-eth0 :
  DEVICE=eth0
  BOOTPROTO=dhcp
  ONBOOT=yes
  
2: service network restart : "Bringing up interface eth0:  Determining IP
information for eth0... failed."  ifup : "Determining IP information for 
eth0... failed."

3: /etc/sysconfig/network-scripts/ifcfg-eth0 :
  DEVICE=eth0
  BOOTPROTO=none
  ONBOOT=yes
  BROADCAST=192.168.210.255
  NETWORK=192.168.210.0
  NETMASK=255.255.255.0
  IPADDR=192.168.210.10


-- 
lisa lorenzin  |  lorenzin at 1000plus.com  |  http://www.1000plus.com/lisa/
of what avail is an open eye if the heart is blind? - solomon ibn gavirol