Simple way that worked for a very long time was adding in /etc/sysctl.conf
net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1
Afterwards sysctl -p for activation of the setting.
It works for a while, but suddenly the IPv6 is enabled.
We are facing two things:
- IPv6 is randomly enabled
- After restart of the server, IPv6 is enabled again.
Checking the proc:
$ cat /proc/sys/net/ipv6/conf/eth0/disable_ipv6 1
I want this disabled, there is a postfix server and gmail is objecting while IPv6 is active.