====== Disable IPV6 ====== You guessed it, we’re going to be working with the command line. I’ll show you how to disable IPv6 on Red Hat- and Debian-based distributions. Here’s how to disable the protocol on a Red Hat-based system: Open a terminal window. Change to the root user. Issue the command : sysctl -w net.ipv6.conf.all.disable_ipv6=1 Issue the command : sysctl -w net.ipv6.conf.default.disable_ipv6=1 To re-enable IPv6, issue the following commands: sysctl -w net.ipv6.conf.all.disable_ipv6=0 sysctl -w net.ipv6.conf.default.disable_ipv6=0 Here’s how to disable the protocol on a Debian-based machine. 1. Open a terminal window. 2. Issue the command sudo nano /etc/sysctl.conf 3. Add the following at the bottom of the file: net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1 4. Save and close the file. 5. Reboot the machine. To re-enable IPv6, remove the above lines from /etc/sysctl.conf and reboot the machine.