Explanation/Reference:
Explanation:
L2TP is not compatible with NAT.
Incorrect Answers:
A: PPTP was designed to provide a way to tunnel PPP connections through an IP network.
B: PPTP uses PPP data packets that encrypted using Microsoft Point to Point Encryption (MPPE), while L2TP on the other hand does not provide any encryption or confidentiality by itself.
D: Radius AAA servers can be configured to use L2TP tunnels.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, pp. 702-703

Explanation/Reference:
Explanation:
Heat-activated detectors provide the earliest warning possible of a fire outbreak. They should be placed below the raised floors as this is where the cabling most likely to cause an electrical fire is.
Heat-activated detectors can be configured to sound an alarm either when a predefined temperature (fixed temperature) is reached or when the temperature increases over a period of time (rate-of-rise). Rate-of- rise temperature sensors usually provide a quicker warning than fixed-temperature sensors because they are more sensitive, but they can also cause more false alarms. The sensors can either be spaced uniformly throughout a facility, or implemented in a line type of installation, which is operated by a heat- sensitive cable.
It is not enough to have these fire and smoke detectors installed in a facility; they must be installed in the right places. Detectors should be installed both on and above suspended ceilings and raised floors, because companies run many types of wires in both places that could start an electrical fire. No one would know about the fire until it broke through the floor or dropped ceiling if detectors were not placed in these areas.
Incorrect Answers:
A: A side wall is not the best location for the sensor. If cabling under a raised floor starts a fire, it will be some time before the wall mounted heat sensor is triggered. Therefore, this answer is incorrect.
B: A variable heat sensor is not the best type of sensor to provide the earliest warning possible of a fire outbreak. Therefore, this answer is incorrect.
C: Fixed-temperature sensors are triggered when a defined temperature is reached. This is not the best type of sensor to provide the earliest warning possible of a fire outbreak. The air vent is also not the best location for the sensor. Therefore, this answer is incorrect.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, p. 470

Something you know and something you have is two authentication factors and is better than a single authentication factor. Strong Authentication or Two Factor
Authentication is widely accepted as the best practice for authentication.
There are three type of authentication factors:
Type 1 - Something you know (password, pin)
Type 2 - Something you have (token, smart card, magnetic card)
Type 3 - Something you are (biometics)
Whenever two of the three types of factors are used together, this is called strong authentication or two factors authentication
The following answers are incorrect:
Establish biometric access through a secured server or Web site:
This is a single factor authentication and it could be weaker than two factors, in most cases it is . Biometric devices can be tricked or circumvented in some cases, this is why they
MUST be supplemented with a second factor of authentication. Multiple attacks have been done on different types of biometric devices. Two factors is always the best to authenticate a user.
Maintain correct and accurate ACLs (access control lists) to allow access to applications:
ACL are attached to objects. They are used within the access control matrix to define what level of access each of the subjects have on the object. It is a column within the Access
Control matrix. This is related to authorization and not authentication.
Allow access only through user ID and password:
This is once again a single factor of authentication because both are something the person knows.

The reverse address resolution protocol (RARP) sends out a packet including a MAC address and a request to be informed of the IP address that should be assigned to that
MAC.
Diskless workstations do not have a full operating system but have just enough code to know how
to boot up and broadcast for an IP address, and they may have a pointer to the server that holds
the operating system. The diskless workstation knows its hardware address, so it broadcasts this
information so that a listening server can assign it the correct IP address.
As with ARP, Reverse Address Resolution Protocol (RARP) frames go to all systems on the
subnet, but only the RARP server responds. Once the RARP server receives this request, it looks
in its table to see which IP address matches the broadcast hardware address. The server then
sends a message that contains its IP address back to the requesting computer. The system now
has an IP address and can function on the network.
The Bootstrap Protocol (BOOTP) was created after RARP to enhance the functionality that RARP
provides for diskless workstations. The diskless workstation can receive its IP address, the name
server address for future name resolutions, and the default gateway address from the BOOTP
server. BOOTP usually provides more functionality to diskless workstations than does RARP.
The evolution of this protocol has unfolded as follows: RARP evolved into BOOTP, which evolved
into DHCP.
The following are incorrect answers:
NAT is a tool that is used for masking true IP addresses by employing internal addresses.
ARP does the opposite of RARP, it finds the MAC address that maps with an existing IP address.
Data Link layer The Data Link layer is not a protocol; it is represented at layer 2 of the OSI model.
In the TCP/IP model, the Data Link and Physical layers are combined into the Network Access
layer, which is sometimes called the Link layer or the Network Interface layer.
Reference(s) used for this question:
Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition, Telecommunications and
Network Security, Page 584-585 and also 598. For Kindle users see Kindle Locations 12348-
12357. McGraw-Hill.
and
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of
Computer Security, John Wiley & Sons, 2001, Chapter 3: Telecommunications and Network
Security (page 87).