MCSA/MCSE Self-Paced Training Kit (Exam 70-270): Installing ...

Objective 6.2 Connect to Computers by Using Dial-Up Networking
26-15
Objective 6.2 Answers
1. Correct Answers: A, B, and E
A. Correct: L2TP tunneling supports IPSec authentication. Point-to-Point Tunneling
Protocol (PPTP) tunneling does not support this type of authentication.
B. Correct: L2TP supports header compression, which reduces the number of bytes
consumed by the header to four. PPTP does not perform header compression, and
as a result, IP headers consume six bytes.
C. Incorrect: Only PPTP automatically provides PPP encryption. L2TP can provide
IPSec encryption.
D. Incorrect: PPTP was the only method of tunneling included with Windows NT
4.0. Windows 2000 and later versions of Windows include both PPTP and L2TP
capabilities.
E. Correct: PPTP connections require only user-level authentication. L2TP/IPSec
connections can require the same user-level authentication and, in addition, computer-level
authentication through a computer certificate.
2. Correct Answers: A
A. Correct: Password Authentication Protocol (PAP) does not support encryption.
As a result, PAP is more vulnerable to attack than other protocols and must be
used only when the remote access client does not support any other method of
authentication.
B. Incorrect: The Shiva Password Authentication Protocol (SPAP) does support
encryption. However, SPAP is not as secure as Challenge Handshake Authentication
Protocol (CHAP) or Microsoft Challenge Handshake Authentication Protocol
(MS-CHAP) because it sends the password across the remote access link using
reversible encryption. Use SPAP only when it is the sole method of authentication
that the client supports.
C. Incorrect: The CHAP transmits authentication information using encrypted, oneway
MD5 hashes. Using a one-way hash is more secure than using reversible
encryption because the user can be authenticated without actually sending the
password to the server.
D. Incorrect: The MS-CHAP provides encrypted authentication in a very similar
manner to CHAP. However, MS-CHAP can also use Microsoft Point-to-Point
Encryption (MPPE) to encrypt data to the client or the server.
E. Incorrect: The Microsoft Challenge Handshake Authentication Protocol version 2
(MS-CHAP v2) provides all the features of MS-CHAP, plus authentication of both
the client and server using one-way encryption. Therefore, MS-CHAP v2 provides
the highest level of security available to users of Windows XP Professional.