[ltp] Detecting a kernel message

[Tod Harter]

I've never heard of a network card being damaged by connecting or 
disconnecting the cable while the machine was powered. I would say from 
experience that its fine. Voltages on ethernet are very low and use very 
little current. 

I must say that your problems echo my own. I've found that with my A20p that 
the built in NIC becomes confused when I unhook from the network and then 
suspend. Afterwards I have to reboot to get back on the LAN. Someone said 
this has to do with APM scripts. 

All I do is when I want to use the modem is I manually issue "ifconfig eth0 
down" and then dial in. Generally I find that the ppp setup system forgets to 
provide a default route though, which means you have to issue "route add 
default gw <ip-addr-of-ppp0>" by hand. Even though I created a couple of 
configs using Mandrake's Drakconf tool it still doesn't happen on its own. 
Personally I've yet to see any of these tools do it properly. The ppp 
subsystem never really properly cleans up the resolve.conf file either, it 
just grows full of "temporary settings" for name service, which you have to 
clean out every so often...

My general opinion of all these configuration tools is that none of them 
really works all that well. There are way too many different ones and they 
all seem half broken. Linuxconf does some things ok but other things it is 
totally broken for, and the same goes for chkconfig, ntsysv, webmin, etc. 
Frankly my answer is to figure out what commands need to be issued for 
various situations, write a script that does it, make it suid root, and just 
run it from a shell at the appropriate time. 

As for monitoring the link beat, I guess you could write a little perl script 
that piped a "tail -f /var/log/messages" and scanned it for what you are 
interested in you could dynamically reconfigure. It just wasn't worth the 
trouble to me.

I know this is a bit wordy, and partly a tangent to your question, but if 
there is one MAJOR place in which linux falls down flat it is just this sort 
of thing. Windows may be annoying as heck, but generally speaking it does a 
much better job of making routine changes like this easy to do. I feel that 
if Linux is to succeed as an end-user platform a LOT more attention needs to 
be paid to this kind of issue. The tools that are out there seem partial, 
badly documented, often broken, and to be quite frank more trouble than they 
are worth. Linux badly needs a single common configuration system that all 
distributions can adhere to. Until that happens only serious bitheads are 
going to be able to use it, and there are many times when I resent the amount 
of effort required to accomplish simple tasks like driver installs and just 
plain routine configuration tasks. The situation is a really nasty mess! 


On Friday 14 September 2001 14:25, you wrote:
> I'm own a thinkpad 380ED with a 3com LAN/Modem PCMCIA card. I use this
> laptop in my work (connecting to the LAN), and working at home (Modem).
> I know about divine and other programs who configure my networking
> options at boot time, but I was looking for some way to make the changes
> "in the fly". That is: working at work, hibernating, then going home and
> just turn on my computer. I already defined two schemes for this needs
> (cardctl scheme modem and cardctl scheme net).
>
> However, I was thinking if its possible to monitor kern.info messages,
> looking for the "lost link beat" and "found link beat" messages, so some
> script could run in the background and change schemes for me.
>
> Is this possible?
> Is this safe (removing and inserting the RJ45 cable without turning off
> the card, but when there isn't any traffic)?
>
> TIA

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