Original reference: thegeekdiary
2. Disable IPv6 using sysctl settings (no reboot required)
1. Append below lines in /etc/sysctl.conf
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
NOTE: To disable IPv6 on a single interface add below lines to /etc/sysctl.conf :
net.ipv6.conf.[interface].disable_ipv6 = 1 ### put interface name here [interface] net.ipv6.conf.default.disable_ipv6 = 1
2. To make the settings effective, execute
# sysctl -p
NOTE: make sure the file /etc/ssh/sshd_config contains the line AddressFamily inet to avoid breaking SSH Xforwarding if you are using the sysctl method
3. Add the AddressFamily line to sshd_config
# vi /etc/ssh/sshd_config
….
AddressFamily inet
….
Restart sshd for changes to get get effect:
# systemctl restart sshd
