• How To Disable IPv6 on Debian 11 / 10 & Ubuntu 20.04 / 18.04

How To Disable IPv6 on Debian 11 / 10 & Ubuntu 20.04 / 18.04
https://www.itzgeek.com/how-tos/linux/debian/how-to-disable-ipv6-on-debian-9-ubuntu-16-04.html

отредактировать файл
/etc/sysctl.conf

...
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.enp0s3.disable_ipv6 = 1
...

sudo sysctl -p

Второй способ

Создать файл:
/etc/sysctl.d/70-disable-ipv6.conf

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.enp0s3.disable_ipv6 = 1

sudo sysctl -p -f /etc/sysctl.d/70-disable-ipv6.conf

sysctl -w net.ipv6.conf.eth1.disable_ipv6=1

How To Disable IPv6 on Debian 11 / 10 & Ubuntu 20.04 / 18.04