You may experience this error shown on “dmesg” or system logs (/var/log/messages) :
IPv6 addrconf: prefix with wrong length 126
This actually indicate a device on your network trying to broadcast IPv6 information that dosen’t match your network configuration.
To get rid and disable this, simply run the following commands as root :
echo 0 > /proc/sys/net/ipv6/conf/eth0/accept_ra
echo 0 > /proc/sys/net/ipv6/conf/eth0/autoconf