C. The “Invalid input detected at ^” terminal message indicates that the IOS understood the configuration command up to the caret marker. This type of message is typical when the command contains a typo. Answer A is the solution for an “Ambiguous Command” message. Answer B is the solution for an “Incomplete Command” message. Answer D is not viable because the terminal session is still connected.

C. NAT Overload uses the source port number to send many unique requests out a single public IP address. Answer A is incorrect because Static NAT performs 1:1 translations from public to private IP addresses. Answer B is incorrect because Dynamic NAT performs many 1:1 translations without requiring manual entries. Answer D is incorrect because NAT Port Mapping is not a valid form of NAT.

A. The show interface command is used to verify the current state of the PPP LCP negotiations. This shows Open, Listen, ACKSent, or TERMSent, depending on the state of LCP at the time (you want LCP to show Open). The other show commands are either irrelevant or would produce invalid syntax.

A, C, D. Telnet, HTTP, and FTP are all protocols supported by Layer 7, or the Application layer of the OSI model. Answer B is incorrect because JPEG is a Layer 6, or Presentation layer, supported protocol.

B. You must use an extended ping to specify the datagram size when pinging an IP address. To do an extended ping in the Cisco IOS, you must be in privileged EXEC mode, and the command is ping without specifying an IP address. Answer A is incorrect because that is a DOS command, not an IOS command. Answer C is incorrect because you do not specify the IP address after the ping keyword. Answer D is incorrect because you must be in privileged EXEC mode.

B. The inside global address is the public address on your router’s external interface. The terminology may seem a little cryptic, but just remember for inside NAT (the style of NAT expected at the CCENT level), the inside/outside terms identify who controls the IP address (inside, you control; outside, someone else controls). The local/global terms identify a private or public address, respectively.

D. DNS resolves hostnames into IP addresses. Answer A is incorrect because SMTP sends email across the network. Answer B is incorrect because NFS allows users with different operating systems (that is, NT and UNIX workstations) to share files. Answer C is incorrect because NNTP offers access to Usenet newsgroup postings.

B. If the boot field in the configuration register is 2-F, the router or switch loads the IOS from flash when no boot system commands are present. Answers A and C will load into ROMmon because the boot field is 0. Answer D has a P in the boot field, which is not a valid hexadecimal character.

B, C. Cisco routers typically support DB-60, which is a 60-pin connection. Only one DB-60 interface is supported per WIC card. Because of this, Cisco developed the Smart Serial connector, which is much smaller and supports more condensed interfaces. Answer A is incorrect because EIA/TIA-449 connects to the CSU/DSU side of the connection. Answer D is incorrect because this is a LAN interface standard.

C. The Session layer of the OSI model handles dialog control among devices and determines the beginning, middle, and end of a session or conversation that occurs between applications (intermediary). The Application layer (Answer A) provides an interface between a host’s communication software and any necessary external applications. The Presentation layer (Answer B) presents data to the Application layer. The Transport layer (Answer D) manages end-to-end connections and data delivery between two hosts.

B, D. During the learning and forwarding STP port states, the switch actively learns MAC addresses it receives on that interface. Answers A and C are incorrect because MAC addresses are not learned during the blocking and listening port states.

A, C. The only private addresses are from the ranges 10.0.0.0 to 10.255.255.255, 172.16.0.0 to 172.31.255.255, and 192.168.0.0 to 192.168.255.255. Because Answers A and C fall outside those ranges, they are considered public IP addresses.

D. SNMP uses port number 161. Answers A and B are incorrect because DHCP uses port numbers 67 and 68. Answer C is incorrect because TFTP uses port number 69.

A, B, C. TCP SYN, smurf, and DDoS are all types of DoS attacks. Answer D is incorrect because trust exploitation is a type of access attack.

A. When a configuration is saved, it is stored in NVRAM as the startup-config. Answer B is incorrect because the running-config is stored in RAM. Answer C is incorrect because POST and ROMmon are located in ROM. Answer D is incorrect because the compressed IOS file is stored in flash.

D. The client ARP table is often cleared during network changes. This can be accomplished using the syntax arp -d * from a command prompt. The * argument instructs the PC to clear all ARP entries rather than just a specific entry.

C. Crosstalk is an electrical or magnetic field that is a result of one communications signal that can affect the signal in a nearby circuit. Answer A is incorrect because EMI is the interference caused by electromagnetic signals. Answer B is incorrect because attenuation occurs over long distances as a signal loses strength. Answer D is incorrect because bandwidth is the total amount of information that can traverse a communications medium measured in millions of bits per second.

C. The transport input ssh command specifies that the vty lines will accept only the SSH - protocol. Answers A and D are incorrect because they are not valid commands. Answer B is a valid command, but it essentially assigns the password ssh-only to the vty lines. It is not specific to SSH.

C. A quick calculation of the subnet addresses defined in the question shows that the server belongs to the 10.5.62.128/27 subnet (addresses 10.5.62.128 to 10.5.62.159) and that the host belongs to the 10.5.62.160/27 subnet (addresses 10.5.62.160 to 10.5.62.191). Because of this, the host needs to contact its default gateway. To accomplish this, the host sends an ARP broadcast request to determine the MAC address of its default gateway.

B. When connecting a switch to a PC, you must use a straight-through UTP cable. Answer A is incorrect because coaxial cable typically is used for cable television. Answer C is incorrect because cross-over cables are used to connect like devices such as switches to other switches or PCs to other PCs. Answer D is incorrect because thin coax (also known as thinnet) is used in older network topologies.

D. Answer D is the false answer because you must configure directly connected classful networks. Thus, 10.2.0.0 is incorrect because the classful network should be 10.0.0.0. Answer B is incorrect because, based on the output, the routing protocol configured is RIPv2 with update authentication. Answer A is incorrect because the administrative distance for RIPv2 is 120; however, the output shows the AD as 80. Answer C is incorrect because the output does show that update authentication is indeed configured.

D. Dynamic NAT allows you to configure multiple pools of IP addresses and translate between them. The router dynamically matches each IP address to one another as a request is made. Answer A is incorrect because Port Address Translation (PAT) is just another name for NAT Overload. Answer B is incorrect. Although Static NAT could perform this task, it would take quite a bit of configuration to manually map IP addresses in large pools. Answer C is incorrect because NAT Overload takes a group of IP addresses and translates them into a single (overloaded) IP address.

A, B, C. 10BASE-2, 10BASE-5, and 10BASE-T are all 10Mbps IEEE 802.3 ethernet standards. Answer D is incorrect because Wi-Fi is a wireless technology that is defined by IEEE 802.11.

C. The summary route for 192.168.64.0 /19 summarizes the networks from 192.168.64.0 /24 to 192.168.95.0 /24. Because 5 bits were stolen (2⁵ = 32), 32 networks are being summarized. Answers A, B, and D are incorrect because they do not fall in the summary range.

A, D. HDLC and PPP are the only encapsulation types supported by Cisco on leased-line connections. Answer B is incorrect because Frame Relay is an encapsulation used on a Frame Relay packet-switched network. Answer C is incorrect because ISDN is a type of circuit-switched technology.

C, D. Hubs and repeaters are hardware devices used at the Physical layer of the OSI model to extend a network. Answers A and B are incorrect because switches and bridges are hardware devices used at the Data Link layer to segment a network.

B, C, D. Unicast, multicast, and broadcast addresses are Ethernet address types used at the 802.3 MAC sublayer. Answer A is incorrect because IP addresses are logical addresses used at the Network layer of the OSI model.

C. The default gateway is a routing device that is responsible for forwarding packets from one segment to another. When configuring the default gateway, you specify the IP address of the routing device. Answers A and B are incorrect because Layer 2 switches are not routing devices. Answer D is incorrect because you do not specify the MAC address when configuring the default gateway.

A, D. The WPA algorithm uses the TKIP algorithm to generate dynamic keys during a wireless session. This helped handle many of the security concerns of WEP. WPA2 (also known as 802.11i) uses the AES encryption algorithm, which is considered one of the best encryption standards available.

B. All multicast addresses start with 0100.5E. Answer A is incorrect because unicast addresses start with the OUI of the manufacturer NIC. Answer C is incorrect because broadcast addresses begin with FFFF.FF. Answer D is incorrect because IP addresses are not ethernet MAC sublayer addresses, and they use dotted-decimal format rather than hexadecimal format.

D. Modems typically are connected to the auxiliary port and are used as a “last-resort” method of accessing the remote router. Answers B and C are incorrect: Because you no longer have IP connectivity to the router, you cannot use SSH and Telnet. Answer A is incorrect because you cannot console into the router because it is in a remote location. The only viable solution left is to call into a modem that is connected through the Auxiliary port.

C. The traceroute (tracert) command can be compared to an enhanced ping. Rather than just testing connectivity to an end device, it tests connectivity to every device in the path, displaying the ping results (delay) for each device as it moves through the network to the destination.

A. Microsegmentation occurs when a switch creates a dedicated path for sending and receiving transmissions with each connected host. Answer B is incorrect because half duplex allows only one-way data transmissions. Answer C is incorrect because full duplex allows two-way data transmissions. Answer D is incorrect because CSMA/CD is an algorithm used for arbitration on an Ethernet network.

D. When a switch receives an unknown unicast, it learns the source MAC address and adds that to the CAM table. It also floods the frame out every port except the one it came in on. Answer A is incorrect because it does not send the frame out the port it came in on. Answer B is incorrect because it does not drop the frame. Answer C is incorrect because Layer 2 switches do not send ARP requests.

B. In the U.S., only three nonoverlapping channels are available for the 2.4GHz band. Europe has four nonoverlapping channels because access to other unlicensed RF bands is available. The moral of the story is that if you’re having trouble finding a free wireless channel in your area, move to Europe.

C, D. Switches and bridges are hardware devices used at the Data Link layer to segment a network. Answers A and B are incorrect because hubs and repeaters are hardware devices used at the Physical layer of the OSI model to extend a network.

B. Class A addresses have a first octet value of 1 to 126. Class B addresses have a first octet value of 128 to 191. Class C addresses have a first octet value of 192 to 223.

B. CDP is a Layer 2 protocol that can be used to discover the Layer 3 addresses of directly attached Cisco devices. Answers A, C, and D are incorrect because these protocols do not provide the Layer 3 address of Cisco devices.

A, C. Multiple users can access the same website at the same time because unique source ports are used to differentiate between the connections. Also, when using NAT with the IP address assigned to the outside interface, you cannot create a static NAT mapping for the entire IP address, because this would make local router services unavailable. Answers B and D are true statements.

C. Entering show cdp neighbor from user or privileged mode uses the Cisco Discovery Protocol (CDP) to discover any directly connected Cisco device. By adding the detail variable for the command, the router displays the IP address information of the remote devices. This powerful command works at the Data Link layer of the OSI model and can discover directly connected devices even if no IP address is configured on the local or remote interface! Answers A and B are incorrect because they are not valid commands. Answer E is incorrect because it shows the IP routing table for the device rather than the neighboring router IP address information.

D. Because the update is coming from two different sources with the same metric, RIP load-balances over both equal paths. Answers A and B are incorrect because the order in which the updates were received is negligible. Answer C is incorrect because the maximum hop count for RIP is 15.

D. 802.1x (less commonly known as Extensible Authentication Protocol over LAN [EAPOL]) adds a secure authentication system to a LAN environment. This technology can be used to secure both wired and wireless LAN connections. The other answers represent varying encryption standards.

B. The first octet is 32+16+8=56. The second octet is 128+32+16+2+1=179. The third octet is 64+16+4+2+1=87. The last octet is 128+64+16+8+2=218. So the address in dotted-decimal format is 56.179.87.218. The last bit in the last octet is 0, which means that any address ending with an odd-numbered octet can be eliminated. All other answers have the wrong decimal conversion.

A. The command to disable CDP on an interface is no cdp enable. The no cdp run command is a global configuration command. Answers B, C, and D are all valid security practices.

A. Cisco routers (new and old) all use a Cisco-proprietary version of HDLC on their serial connections. Although an industry-standard HDLC exists, very few vendors support it. Answer B is incorrect because there are no “backward-compatible” WAN standards. Answers C and D are incorrect because newer Cisco routers still use the Cisco-proprietary HDLC as the default encapsulation.

C. The broadcast IP of 212.84.5.66/26 is 212.84.5.127. The next network ID after 212.84.5.64 is 212.84.5.128. To determine the broadcast IP, you subtract 1 from the next network ID, which in this case is 212.84.5.127. All other answers are incorrect because they are not the broadcast IP.

B. Because the 10.1.100.0/24 network is a RIP-learned subnetted network, it must have been learned via RIPv2, because RIPv2 can be classless. If the routing protocol were RIPv1, the network would be summarized to its classful boundary and would show up in the routing table as 10.0.0.0/8. Answer A is incorrect because the network is 14 hops away, as indicated by the [120/14]. Answer C is incorrect because Serial 0 has an IP address of 192.168.1.8, displayed as the connected interface entry. Answer D is wrong because the maximum hop count for RIP is 15.

B. The Cisco Wireless IPS system identifies rogue wireless access points added to the network. The 802.1x and the Cisco ACS Server are primarily responsible for user authentication and privileges. MAC address security can help disable a port with a rogue wireless access point, but it cannot detect the rogue’s existence.

B. The Network ID of 212.84.5.66/26 is 212.84.5.64. The CIDR notation represents subnet mask 255.255.255.192. The binary equivalent of the subnet mask host field is 11000000. The binary equivalent of the 212.84.5.66 host field is 01000010. Using Boolean AND, the Network ID is 212.84.5.64. Answers A, C, and D are incorrect.

B, C. When pinging a remote device, the destination IP address is the IP address of the remote device. The MAC address, however, is the default gateway for that segment. Answer A is incorrect because the destination IP address is not the default gateway, because that is not the IP’s destination. Answer D is incorrect because the default gateway is the destination address for the data-link segment.

A, B, E. The five primary standards that are used for serial interface connections (to the CSU/DSU) are V.35, X.21, EIA/TIA-232, EIA/TIA-449, and EIA/TIA-530. Answers C and D are incorrect because RJ-48 is the standard for a T1 connection, and RJ-44 is not a defined standard.

A. The c2600 portion of the IOS filename represents the hardware platform. In this case, it is a Cisco 2600 series router. Answer B is incorrect because the term ipbase refers to the IP Base feature set. Answer C is incorrect because the train identifier is T for Technical. Answer D is incorrect because the IOS version is represented by 122, or version 12.2.

D. The terminal monitor command copies and consoles messages to the Telnet sessions of an IOS router or switch. This command is done in privileged EXEC mode in the device you are Telnetted into. Answers A, B, and C are incorrect because they are either on the wrong router or in the wrong mode.

C. The key line in the output is “DTE V.24 (RS-232) clocks stopped.” This indicates that the interface is connected but is not receiving a clock rate from the opposite site of the connection. When you see this single line of output, all other answers (A, B, and D) become irrelevant.

C. The lowest bridge ID becomes the root bridge. Because all devices have the same priority (1024), the lowest MAC address is the tie-breaker. Answers A, B, and D are incorrect because they have a higher Bridge ID than Answer C.

D. Power over Ethernet is a technology that allows an end device to receive power over a copper Ethernet cable. Answer A is incorrect because Long-Reach Ethernet (LRE) is an Ethernet specification developed by Cisco to provide broadband service over existing telephone-grade or Category 1, 2, or 3 wiring. Answers B and C are incorrect because Gigabit Ethernet and Fast Ethernet standards do not include the ability to supply power to an end device.

B. Because this is a Layer 2 switch, the gateway of last resort is configured by setting the default gateway. Answers A and C are incorrect because you cannot configure a default route or a default network in a Layer 2 switch. Answer D is not a valid command.

D. An Extended Service Set (ESS) wireless topology is the combination of two or more Basic Service Set (BSS) networks. This allows client roaming (between wireless cells) without service interruption.

B, E, and F. To secure your console connection when you walk away from the IOS terminal, you need to decrease the exec-timeout and set the login and password. These configurations must be performed in line configuration mode. All other answers are incorrect because they are performed in the wrong configuration mode.

D. Answers A, B, and C are true because you must configure a hostname and domain name for the device and generate an RSA key from that information. In addition, you must configure a username and password for the SSH to authenticate. As soon as the RSA key is generated, SSH is automatically enabled, so Answer D is false.

D. NAT can accomplish some pretty amazing feats, but sharing an IP address for two servers that use the same port number is not one of them. In this case, you need two public Internet addresses to allow both internal web servers to be accessed on TCP port 80. The other servers can use port 21 (FTP) and port 25 (SMTP) on either of the public Internet IP addresses. Answer A could be used to solve this problem, but it is not the best solution, because it would be more costly to deploy than Answer D. Answer B is incorrect because NAT Overload lets the servers share a single IP address only when accessing the Internet, not when the requests originate from the Internet. Answer C is incorrect because you could only map TCP port 80 on the single IP address to one of the internal web servers. The other could not be accessed from the Internet.

A, D. The port becomes disabled if a BPDU is detected on a BPDU Guard-enabled port, as well as if there is a port security violation. Answers B and C are incorrect because that would cause the port to be in a blocking state.

C. If the device that is being pinged is not in the local ARP cache, the pinging device must first do an ARP request for the device. Typically, the time it takes to resolve this causes the first ping to time out. Answer A is false because interfaces don’t sleep. Answer B is incorrect because all pings would time out if the IP protocol stack were failing. Answer D is incorrect because the local switch will flood the frame and will not delay the ping to cause a timeout.

A, B. To disconnect the Telnet session, you can enter disconnect followed by the session number in the originating router. Or you can press the Enter key to resume the Telnet session and enter exit in the device you are Telnetted into to close the Telnet session. Answer C is incorrect because pressing Enter first resumes your session with the remote router and causes the disconnect command to fail. Answer D is incorrect because it is invalid syntax.

C. You do not specify a subnet mask when configuring RIPv2. Answers A, B, and D are incorrect because you do enter the RIP routing process and advertise directly connected classful networks and specify the version as 2.

D. When connecting to a hub, you must have the port running in half duplex, because CSMA/CD must be enabled. Answer A is incorrect because the speed is irrelevant. Answer B is incorrect because you can run full duplex when connecting to switches. Answer C is incorrect because it does not matter what cable is used.

A. RIPv2 has update authentication, multicasts updates to 224.0.0.9, and can support classless routing. Answer A is not a feature because it is still a distance vector routing protocol that sends continuous updates every 30 seconds instead of Hello messages, such as RIPv1.

D. IPv6 addresses have 128 bits. Answer A is the bit count for an IPv4 address. Answers B and C are incorrect because they are not valid IP address bit counts.

A, B, D. IPsec, SSL, and SSH are all encryption protocols. Answer C is incorrect because NTP (Network Time Protocol) synchronizes clocks on a network.

C. Unique/site-local addresses are the private address space for IPv6. Answer A is incorrect because link-local addresses represent the address automatically assigned to a device at Layer 2. Answer B is incorrect because a global address is a public IP address. Answer D is incorrect because a multicast address in IPv6 is the same as a broadcast IP address.