How to disable ipv6 in ubuntu linux

FREQUENTLY ASKED QUESTIONS (Ubuntu)
Q: How to disable IPv6 in ubuntu linux?

Disable IPv6 if you do not use in your network.
Edit the sysctl configuration file in /etc/ directory 


user@ubuntu:~$ sudo vi /etc/sysctl.conf
#Add the below line to bottom of the "sysctl.conf" file
net.ipv6.conf.all.disable_ipv6=1
#(save the file)

click to enlarge (disable ipv6 in ubuntu)

And now reboot your ubuntu machine
user@ubuntu:~$ sudo reboot


Verify the IPv6 is disabled
user@ubuntu:~$ ifconfig                 (verify ipv6 address is not showing)

LABELS: Debian, extra-tips, FAQ, How-To, IPv6, linux, Ubuntu