[SOLVED] Interface which utilize TWO IP addresses

[techilog]

Hello everybody!

I have two subnetworks from my ISP:

1. 200.100.20.17/30
2. 200.100.25.1/27

I am trying to build a router/firewall which have configuration like that:

WAN - 200.100.20.17/30
LAN - 10.0.0.1/24 with ability to utilize 200.100.25.1/27 addresses

I am not willing to use real IP addresses from subnet 200.100.25.1/27 for every computer in the network, but only for some of them.

In another words, I would like to make it possible to configure one computer with IP 200.100.25.2 and GW 200.100.25.1(LAN IP address). BUT I would like to make it possible to optionally set on the same computer IP 10.0.0.2 and GW 10.0.0.1 (of course not at the same time)

Please let me know if there is such possibility in pfSense
Many thanks for reading this topic!

[techilog]

I think, I have described my question not as clear as I should
What I wanted, was to allow multiple subnets on one interface

Luckily i have found an answer here:
http://doc.pfsense.org/multiple-subnets-one-interface-pfsense.pdf