Disable IPv6

From TrustixWiki

How to disable IPv6

Disable autoload of protocol 10 (ipv6) within /etc/modprobe.conf:

 alias net-pf-10 off

Make sure ipv6 module is not loaded within initrd:

• remove ipv6 from /etc/mkinitrd/modules
• generate new initrd

 $ mkinitrd -o /boot/initrd-<your-kernel-version>.img <your-kernel-version>

After reboot ipv6 support is disabled.