Which of the following choices lists the ports that Microsoft internal networking uses that should be blocked from outside access?

A.
UDP 137 and 138, and TCP 139

B.
Ports 11, 112, and 79

C.
UDP 1028, 31337 and 6000

D.
Port 80, 134 and 31337
1D0-470

Explanation:
UDP & TCP 137 are used for NETBIOS name service. UDP 138 is used for the NETBIOS Datagram Service, and TCP 139 is used for the NETBIOS Session Service. Internal networking for Microsoft Windows systems uses NETBIOS for its redirector. Hacking into the Windows systems would be blocked if NETBIOS could not pass through the firewall. To logon to Windows, or access file or printer shares, access will have to be done via SMB (Service Message Blocks) which ride on NETBIOS.
Incorrect Answers:
B: 11 is systat, 112 is not used, and 79 is finger. Although you might want to block out these ports, including port 79 (finger) which can expose server information to a hacker, these are not part of Microsoft internal networking.
C: These ports are outside of the well known ports, and blocking them does not close any holes. These ports are not part of Microsoft internal networking.
D: Port 80 is HTTP, so to block it disables web browsing. Port 134 is not assigned to a service, and port 31337 is not a well known port. These ports are not part of Microsoft internal networking.