OpenVZ supports VPN inside a container via kernel TUN/TAP module and device. To allow VPS #101 to use the TUN/TAP device the following should be done:
#101 – VPS  id. Replace #101 with your VPS id.
Make sure the tun module has already loaded on the Node.
[[email protected] /]#  lsmod | grep tun
If not listed, then load the tun module with the below command
[[email protected] /]# modprobe tun [[email protected] /]#  lsmod | grep tun
  tun                    82432  6

Run the following command in Node:
[[email protected] /]#  vzctl set 101 --devnodes net/tun:rw --save
[[email protected] /]#  vzctl set 101 --devices c:10:200:rw --save 
[[email protected] /]#  vzctl stop 101 
[[email protected] /]#  vzctl set 101 --capability net_admin:on --save
[[email protected] /]#  vzctl start 101 
[[email protected] /]#  vzctl exec 101 mkdir -p /dev/net
[[email protected] /]#  vzctl exec 101 chmod 600 /dev/net/tun 

To check TUN/TAP is enabled or not :
[[email protected] /]# vzctl enter 101
Inside the VPS: 
[[email protected] /]# cat /dev/net/tun
cat: /dev/net/tun: File descriptor in bad state     

# It means the TUN/TAP is enabled on your VPS.
 cat: /dev/net/tun: No such device     

#  If you receive like this, then the TUN/TAP has not enabled on your VPS . Try to enable TUN/TAP again and check.