You have a computer that runs Windows 7. IPv6 is disabled on the computer.

The computer has the following IPv4 settings:

* IP address: 10.1.1.193
* Subnet mask: 255.255.0.0
* Default gateway: 10.1.1.194
* Preferred DNS server: 10.1.1.195

You need to ensure that the computer can only communicate with computers on the local subnet.

What should you do?

A.
Delete the default gateway address.

B.
Delete the preferred DNS server IP address.

C.
Configure the subnet mask to use 255.255.255.0.

D.
Configure the subnet mask to use 255.255.255.192.

Explanation:
Why gateways work
Default gateways are important to make IP routing work efficiently. In most cases, the router that acts as the default gateway for TCP/IP hosts–either a dedicated router or a computer that connects two or more network segments–maintains knowledge of other networks in the larger network and how to reach them.

TCP/IP hosts rely on default gateways for most of their communication needs with hosts on remote network segments. In this way, individual hosts are freed of the burden of having to maintain extensive and continuously updated knowledge about individual remote IP network segments. Only the router that acts as the default gateway needs to maintain this level of routing knowledge to reach other remote network segments in the larger internetwork.

If the default gateway fails, communication beyond the local network segment may be impaired. To prevent this, you can use the Advanced TCP/IP Settings dialog box (in Network Connections) for each connection to specify multiple default gateways. You can also use the route command to manually add routes to the routing table for heavily used hosts or networks.