Hi Bluemerlin
look at your /etc/sysctl.conf
and make sure you have enabled ipv4 forwarding.
IF NOT this helps:
echo 1 > /proc/sys/net/ipv4/ip_forward
echo 'net.ipv4.ip_forward=1' >> /etc/sysctl.conf
and if you want use ipv6 in your guest
echo 1 > /proc/sys/net/ipv6/conf/all/proxy_ndp...