help: DHCP & cable-modem

Scot L. Harris webid at
Sun Jul 4 05:00:23 UTC 2004

On Sun, 2004-07-04 at 00:06, javac at wrote:
> my mailbox overflowed, doh!  looking in the archive i saw the suggestion that it might be a signal strength problem.  i can't recall what the modem lights were doing, exactly, but... i believe all the different lights were merrily twinkling (both times) and the computer would just hang forever at "initializing eth0" IIRC.
> kinda just waiting for it to happen again.  the only solution i've found is the most drastic total re-install.  that the re-install immediately works indicates the problem isn't with the hardware.
> thanks,

Ouch!  Total reinstall should never be needed in such a case.  

If it happens again try restarting the interface.

ifdown eth0
ifup eth0

Should force it to get an address via DHCP.  If it does not then more
info is needed to try and figure out what the problem is.

On the cable modem there is typically one LED that is marked cable. 
That LED should be steady green indicating the modem has a connection
back to the ISP.  If it is blinking then the modem has lost connection
to the ISP.  There should be another LED indicating activity and it
should be blinking if there is traffic.

The other thing to check when this happens again is to see if the IP
address changes.

Do a     ifconfig -a     and save the info, print it out if you have
to.  This should include your current IP address.  When it happens again
and you get reconnected run ifconfig -a again and compare the IP
addresses.  If they are different then the ISP changed the IP address on
you and could indicate that is the source of the problem.

If they are changing the IP address the ifdown and ifup should get you
back on line.  

If the IP address is the same then the ISP probably is not the issue and
you will need to look harder at your setup.

Also take a look through your /var/log/messages file looking for
anything that may have happened around the time the connection was lost.

Scot L. Harris
webid at

"Today, of course, it is considered very poor taste to use the F-word
except in major motion pictures."
		-- Dave Barry, "$#$%#^%!^%&@%@!" 

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