IP masquerade (also known as Internet Connection Sharing) is a feature for sharing a single Internet connection on one computer between other computers on the same local area network. It makes use of DHCP and NAT.
IP masquerade routes TCP/IP packets from a small LAN to the Internet. IP masquerade maps individual IP addresses of local computers to unused port numbers in the TCP/IP stack. Due to the nature of the NAT, IP addresses on the local computer are not visible on the Internet. All packets leaving or entering the LAN are sent from or to the IP address of the external adapter on the computer performing IP masquerade.
The server will always have the IP address 192.168.0.1 and will provide NAT services to the whole 192.168.0.x subnet, even if the address on the client was set manually, not by the DHCP server. (not really, any private IP subnet, like 192.168.x.x or 10.x.x.x, is valid)
ToDo: rename the page (ICS is Microsoft jargon)