Chapter 4: Communication and Network Security (Domain 4) 357
because they may have to be passed without any inspection. Christmas tree attacks set all
of the possible flags on a TCP packet (and are thus related to an IP protocol), IPX is not
an IP-based protocol, and while these protocols are outdated, there are ways to make even
modern PCs understand them.- C. Of the three answers, PEAP is the best solution. It encapsulates EAP in a TLS tunnel,
providing strong encryption. LEAP is a Cisco proprietary protocol that was originally
designed to help deal with problems in WEP. LEAP’s protections have been defeated,
making it a poor choice. - A. L2TP can use IPsec to provide encryption of traffic, ensuring confidentiality of the
traffic carried via an L2TP VPN. PPTP sends the initial packets of a session in plaintext,
potentially including usernames and hashed passwords. PPTP does support EAP and was
designed to encapsulate PPP packets. All VPNs are point to point, and multipoint issues
are not a VPN problem. - C. A full mesh topology directly connects each machine to every other machine on the
network. For five systems, this means four connections per system. - D. Ethernet uses a bus topology. While devices may be physically connected to a switch in
a physical topology that looks like a star, systems using Ethernet can all transmit on the
bus simultaneously, possibly leading to collisions. - D. ARP spoofing is often done to replace a target’s cache entry for a destination IP,
allowing the attacker to conduct a man-in-the-middle attack. A denial of service attack
would be aimed at disrupting services rather than spoofing an ARP response, a replay
attack will involve existing sessions, and a Trojan is malware that is disguised in a way
that makes it look harmless. - B. Category 3 UTP cable is primarily used for phone cables and was also used for early
Ethernet networks where it provided 10 Mbps of throughput. Cat 5 cable provides 100
Mbps (and 1000 Mbps if it is Cat 5e). Cat 6 cable can also provide 1000 Mbps. - B. Crosstalk occurs when data transmitted on one set of wires is picked up on another
set of wires. Interference like this is electromagnetic rather than simply magnetic,
transmission absorption is a made-up term, and amplitude modulation is how AM radio
works. - B. WEP’s implementation of RC4 is weakened by its use of a static common key and a
limited number of initialization vectors. It does not use asymmetric encryption, and clients
do not select encryption algorithms. - B. VLANs can be used to logically separate groups of network ports while still providing
access to an uplink. Per-room VPNs would create significant overhead for support as well
as create additional expenses. Port security is used to limit what systems can connect to
ports, but it doesn’t provide network security between systems. Finally, while firewalls
might work, they would add additional expense and complexity without adding any
benefits over a VLAN solution.