tech.safesquid.com

Enabling the IPv6 can be done in two ways.

* Enabling IPv6 in kernel module:
---------------------------------------------
1. Need to edit /etc/default/grub and change the value of kernel parameter ipv6.disable from 1 to 0 in line GRUB_CMDLINE_LINUX.
Changes made at Kernel module requires reboot.
Note: ipv6.disable=0 is the default value, so you can simply remove this argument ipv6.disable from GRUB_CMDLINE_LINUX argument list.
2.Regenerate a GRUB configuration file and overwrite existing one using the command.
update-grub
Below grub update should be done without error like below. 3.Restart system for the changes to take effect.
shutdown -r now

*Enabling IPv6 using sysctl settings:
-------------------------------------------------
Even if the IPv6 kernel module is loaded, it could also be disabled by using sysctl settings.
1. In order to enable IPv6, please make sure below lines in /etc/sysctl.conf are commented out or removed or change 1 to 0 cat /etc/sysctl.conf | grep ipv6
net.ipv6.conf.all.disable_ipv6 = 0 ## either comment/remove this line or change its value from 1 to 0
net.ipv6.conf.default.disable_ipv6 = 0 ## either comment/remove this line or change its value from 1 to 0
2. Use the command ‘sysctl -p’ to re-read the configuratiion file /etc/sysctl.conf.
sysctl -p
Changes made at sysctl settings required no reboot.

Verification:
To Verify IPv6 is enabled or not can be checked by: