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:
1090 40148
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 connectionto
specify multiple default gateways. You can also usethe route command to manually add routes to the routing
table for heavily used hosts or networks.