after i got up my ubuntu server i checked the syslog where the kernel kept griping about the following.
IPv6 addrconf: prefix with wrong length 48
To keep the syslog clean i searched for a way to suppress that message. it´s simple.
In /etc/sysctl.conf i add two lines
net.ipv6.conf.all.accept_ra = 0 net.ipv6.conf.all.autoconf = 0
There you go.