Disable IPv6 in kernel module (requires reboot)
1. Edit /etc/default/grub and add ipv6.disable=1 in line GRUB_CMDLINE_LINUX, e.g.:
# cat /etc/default/grub GRUB_TIMEOUT=5 GRUB_DEFAULT=saved GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT="console" GRUB_CMDLINE_LINUX="ipv6.disable=1 crashkernel=auto rhgb quiet" GRUB_DISABLE_RECOVERY="true"
2. Regenerate a GRUB configuration file and overwrite existing one:
# grub2-mkconfig -o /boot/grub2/grub.cfg
3. Restart system and verify no line “inet6” in “ip addr show” command output.
# shutdown -r now
# ip addr show | grep net6