networking - How to assign multiple IPv6 Alias addresses to one network interface

I have an IPv6 Range which i am trying to assign on a centos6 server. I have updated my below files for IPv6 configuration:

[root@test ~]# cat /etc/sysconfig/network
NETWORKING=yes
NETWORKING_IPV6=yes
HOSTNAME=test.techsuccor.com

[root@test ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 
DEVICE=eth0

HWADDR=82:d7:5d:50:c9:86
TYPE=Ethernet
UUID=8ea314f3-d89a-4a5c-9ede-64b6675cae71
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=none
IPADDR=180.149.X.X
NETMASK=255.255.255.0

DNS2=206.183.X.X

GATEWAY=180.X.X.X
DNS1=206.X.X.X
IPV6INIT=yes
USERCTL=no
IPV6ADDR=2001:0df3:3cXX::X/64
IPV6_DEFAULTGW=2001:0df3:3cXX::1
[root@test ~]# 

With the above configuration am able to ping the single main ipv6 ipaddress in & out.

Using the IPV6ADDR_SECONDARIES option am also able to add Alias IP's and ping them in and out

IPV6ADDR_SECONDARIES="2001:0df3:3cXX::X1/64 \
2001:0df3:3cXX::X2/64 \
2001:0df3:3cXX::X3/64 \
2001:0df3:3cXX::X4/64 \
2001:0df3:3cXX::X5/64"

What I actually need to do is assign full ipv6 range to the single NIC as alias ip's in one go. I can do this with below command

[root@test ~]# for ip in {4..10}; do /sbin/ifconfig eth0:1 inet6 add 2001:0df3:3c00::${ip}/64; done

Also after I run this command, I see my ipv6 ip's with ifconfig command as below but only the main IPv6 ping's and none of the Alias Ip ping from outside. Also is restart newtork all ip's go away.

[root@test ~]# ifconfig 
eth0      Link encap:Ethernet  HWaddr 82:D7:5D:50:C9:86  
          inet addr:180.149.XX.XX  Bcast:180.149.XX.XX Mask:255.255.255.0

          **inet6 addr: 2001:df3:3c00::10/64 Scope:Global
          inet6 addr: 2001:df3:3c00::1/64 Scope:Global
          inet6 addr: 2001:df3:3c00::3/64 Scope:Global
          inet6 addr: 2001:df3:3c00::4/64 Scope:Global
          inet6 addr: 2001:df3:3c00::5/64 Scope:Global
          inet6 addr: fe80::80d7:5dff:fe50:c986/64 Scope:Link
          inet6 addr: 2001:df3:3c00::6/64 Scope:Global
          inet6 addr: 2001:df3:3c00::7/64 Scope:Global
          inet6 addr: 2001:df3:3c00::8/64 Scope:Global
          inet6 addr: 2001:df3:3c00::9/64 Scope:Global**

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:312539319 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1808219 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:22772397919 (21.2 GiB)  TX bytes:312003644 (297.5 MiB)
          Interrupt:165 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host

          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:16406 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16406 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:2295915 (2.1 MiB)  TX bytes:2295915 (2.1 MiB)