To disable IPv6 Temporary

sudo sh -c 'echo 1 > /proc/sys/net/ipv6/conf/<interface-name>/disable_ipv6'

note: <interface-name> change to "all" for all interface



Disable IPv6 Permanently across Reboots

open /etc/sysctl.conf

add

# to disable IPv6 on all interfaces system wide

net.ipv6.conf.all.disable_ipv6 = 1



# to disable IPv6 on a specific interface (e.g., eth0, lo)

net.ipv6.conf.lo.disable_ipv6 = 1

net.ipv6.conf.eth0.disable_ipv6 = 1

Save.

Thanks.