From Fedora Project Wiki
< Tools | NetworkManager
For debugging NetworkManager in a more or less clean environment, you can use the following script. It kills NetworkManager and dhclient instances, sets down eth0 and eth1, flushes global addresses and starts NetworkManager with debug saved into ~/nm.debug.
#!/bin/bash -x NM="/opt/NetworkManager/sbin/NetworkManager" KILL="NetworkManager dhclient" LINKS="eth0 eth1" DEBUG="$HOME/nm.debug" for name in $KILL; do killall $name 2>/dev/null && echo "TERM: $name" && sleep 1 killall -9 $name 2>/dev/null && echo "KILL: $name" && sleep 1 done ps -ef | grep -iE 'network|dhc' | grep -v ' grep -iE ' for link in $LINKS; do ip link set $link down done ip address flush scope global sleep 1 $NM --no-daemon --log-level=debug 2>$DEBUG