IPv6 stack is enabled in the kernel but there is no interface that has ::1 address assigned

Freeipa installation gives following error while Installing. 

Error:

[root@freeipa /]# ipa-server-install
ipapython.admintool: ERROR    IPv6 stack is enabled in the kernel but there is no interface that has ::1 address assigned. Add ::1 address resolution to 'lo' interface. You might need to enable IPv6 on the interface 'lo' in sysctl.conf.
ipapython.admintool: ERROR    The ipa-server-install command failed. See /var/log/ipaserver-install.log for more information

Solution:

Edit the sysctl.conf file and add following entry

[root@freeipa /]# vi /etc/sysctl.conf
net.ipv6.conf.lo.disable_ipv6 = 0

Run sysctl -p to load the config

[root@freeipa /]# sysctl -p
net.ipv6.conf.lo.disable_ipv6 = 0
[root@freeipa /]#

verify that ipv6 Enabled.

[root@freeipa /]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever

Now run the "ipa-server-install" command