When I asked my what is my static IP leases, I got the reply:
ISP WAN : xxx.xxx.228.117
Customer WAN: xxx.xxx.228.118
Lan IP: xxx.xxx.194.112-127
May I ask What is the ISP WAN and Customer WAN?
Sounds something like this:
The x.x.228.117 and 118 addresses are used on the link between your WAN router (or firewall or whatever it happens to be) and your ISP.
Since they've specified the range of .112-.127 for the LAN, I'm assuming that's actually the xxx.xxx.194.112/28 subnet. The first address of the subnet (.112) is the network address, so you can't assign it. The last address (.127) is the broadcast address, so you can't assign it either. You need to assign one of the addresses in that range to the LAN interface of your router/firewall (I've chosen .113 in the diagram). That leaves you with 13 addresses that you can actually use to assign to hosts (.114-.126).
The default gateway of your hosts would be configured as xxx.xxx.194.113. The default gateway of your router/firewall would be configured as xxx.xxx.228.117. That way the hosts know to use your router to get to the Internet, and your router knows to use your ISP to get to the Internet.
The "ISP WAN" is your ISP's gateway address. It will act as the upstream gateway for your router. The "Customer WAN" is your router's external IP address. The "LAN IP" is the publicly-routable network block to assign to your hosts behind the router.