Отключение ipv6 ubuntu 20.04,18.04 и т.д.

1 способ:

# mcedit /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1"

# update-grub

2 способ:
# mcedit /etc/sysctl.conf

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

# sysctl -p