disable ipv6 debian

To disable IPv6 on selected hosts in LANs with ipv6 router advertisements.

Disable the ipv6 address taken temporarily
# ip -6 addr del 2001:cafe:b0b0:abcd:6ef0:49ff:fe0e:f1b9/64 dev eth0
# ip -6 addr del fe80::6ef0:49ff:fe0e:f1b9/64 dev eth0 

Disable the ipv6 stack permanently
# echo net.ipv6.conf.all.disable_ipv6=1 > /etc/sysctl.d/disableipv6.conf
# sysctl -p

More: Debian - turn off IPv6

In case you want to disable IPv4 and enable IPv6 only on a host.
example /etc/network/interfaces
auto eth0
iface eth0 inet manual
iface eth0 inet6 auto

If you don't have an IPv6 DNS caching server find a public one in the public dns servers list

debian linux disable IPv6