How to disable IPv6 addresses on a Plesk server?

Question

How to disable IPv6 addresses on a Plesk server?

Answer

In order to disable IPv6, the following steps should be performed:

1. Go to Tools & Settings > IP Addresses > 2001:db8:f61:a1ff:0:0:0:80 > the Sites column. If there are sites hosted on IPv6, go to Domains > example.com > Web Hosting Access and set the field IPv6 address to None:
   

2. Log in to the server via SSH and add the following lines to /etc/sysctl.conf :

   # grep ipv6 /etc/sysctl.conf
   net.ipv6.conf.all.disable_ipv6=1
   net.ipv6.conf.default.disable_ipv6=1

3. Apply the settings from the /etc/sysctl.conf via the following command:

   # sysctl -p

4. Remove IPv6 addresses from the Plesk

   Note: It can be done either manually or by pressing the Reread IPs button in Tools & Settings > IP Addresses

Additional Information

How to enable IPv6 addresses on a Plesk server?