Virtual IP?

[park0kyung0won]

Hi

Is virtual IP (alias) assigning multiple IP addresses for one interface of the firewall?
I want to do 1:1 NAT using virtual IPs

I want to map 10.180.20.X (Virtual IP assigned to WAN interface on firewall) to
192.168.20.X (Some machine inside LAN)

How can I easily add range of IP for virtual IPs?