From Bugzilla Helper:
User-Agent: Mozilla/4.78 [en] (X11; U; Linux 2.4.16 i686)

Description of problem:
When automatically bringing up an ethernet interface, the current scripts
assume the port to be connected. This is a problem for laptops
such as the ThinkPad T21 which has ethernet built-in if they are not
connected (rather common): during boot or resume there is a 2-3 minute
delay because dhcpd has to time out.

Version-Release number of selected component (if applicable):


How reproducible:
Always

Steps to Reproduce:
1. remove the ethernet cable from your system
2. ifdown eth0; ifup eth0
3.
	

Actual Results:  dhcp time out

Expected Results:  ifup tries to detect a link beat first and exit 0's if
there is none

Additional info:

To fix this bug:
mii-diag.c from www.scyld.com/diag is a GPLed program to detect link
status. Assuming this to be in /sbin, add the following to /sbin/ifup:
   if [ "${DEVICETYPE}" = "eth" -a -x /sbin/mii-diag ]; then 
      /sbin/mii-diag -s ${DEVICE} > /dev/null 
      if [ $? != 0 ]; then 
         echo "no link beat found: ${DEVICE} seems not connected"
         exit 0 
      fi 
   fi 
after the line
   echo -n $"Determining IP information for ${DEVICE}..."