Although IPv6 has many advantages over IPv4, few organizations have implemented IPv6. If IPv6 is not to be used, it is recommended that it be disabled to reduce the attack surface of the system.
Solution
Edit /etc/default/grub and add ' ipv6.disable=1' to GRUB_CMDLINE_LINUX: GRUB_CMDLINE_LINUX='ipv6.disable=1' Run the following command to update the grub2 configuration: # grub2-mkconfig > /boot/grub2/grub.cfg