How do I add or remove an IP address to a VPS?
To add IP address 192.168.0.1 to VPS 101 run the following command on the hardware node:
# vzctl set 101 --ipadd 192.168.0.1 --save
To release an IP address from a VPS use the similar command with --ipdel option.
Please, note that it's impossible to add an IP address from inside a VPS.