Prefer IPv4 in LAN

from https://askubuntu.com/questions/32298/prefer-a-ipv4-dns-lookups-before-aaaaipv6-lookups

# For sites which prefer IPv4 connections change the last line to
# precedence ::ffff:0:0/96 100
#
#    For sites which use site-local IPv4 addresses behind NAT there is
#    the problem that even if IPv4 addresses are preferred they do not
#    have the same scope and are therefore not sorted first.  To change
#    this use only these rules:
#
scopev4 ::ffff:169.254.0.0/112  2
scopev4 ::ffff:127.0.0.0/104    2
scopev4 ::ffff:0.0.0.0/96       14