| The following sections provide you with the opportunity to review what you learned in this chapter and to test yourself. The Facts For the exam, don't forget these important concepts: A Class A address uses only the first octet to represent the network portion, a Class B address uses two octets, and a Class C address uses three octets. Class A addresses span from 1 to 126 with a default subnet mask of 255.0.0.0. Class B addresses span from 128 to 191 with a default subnet mask of 255.255.0.0. Class C addresses span from 192 to 223 with a default subnet mask of 255.255.255.0. The 127 network ID is reserved for the local loopback. A valid IPv6 address is 42DE:7E55:63F2:21AA:CBD4:D773:CC21:554F. A public network is a network to which anyone can connect, such as the Internet. Subnetting enables bits from the node portion of an IP address to be used to create more network addresses. A private network is any network to which access is restricted. Reserved IP addresses are 10.0.0.0, 172.16.0.0 172.31.0.0, and 192.168.0.0. Without a default gateway, connectivity is limited to just the local network segment. IP addresses can be assigned dynamically, via DHCP, or statically. In addition, some platforms such as Windows support APIPA addressing. On a Windows platform, APIPA assigns addresses from the 169.254.x.x address range. DNS resolves hostnames to IP addresses. NAT/ICS translates private network addresses into public ones. WINS resolves NetBIOS names to IP addresses. SNMP provides network-management facilities on TCP/IP-based networks. SMB, NFS, and AFP are file access/sharing mechanisms used on Windows, UNIX/Linux and Apple Macintosh, respectively.
Exam Prep Questions | 1: | What is the function of ARP? A. It resolves IP addresses to MAC addresses. B. It resolves NetBIOS names to IP addresses. C. It resolves MAC addresses to IP addresses. D. It resolves hostnames to IP addresses.
| | 2: | As the network administrator, you decide to block port 80. Which of the following services will be unavailable for network users? A. DNS B. POP3 C. FTP D. HTTP
| | 3: | Which of the following addresses is a Class B address? A. 129.16.12.200 B. 126.15.16.122 C. 211.244.212.5 D. 193.17.101.27
| | 4: | You are the administrator for a network with 2 Windows Server 2003 systems and 65 Windows XP Professional systems. At 10 a.m., three users call to report that they are experiencing network connectivity problems. Upon investigation, you determine that the DHCP server has failed. How can you tell that the DHCP server failure is the cause of the connectivity problems experienced by the three users? A. When you check their systems, they have an IP address of 0.0.0.0. B. When you check their systems, they have an IP address in the 192.168.x.x address range. C. When you check their systems, they have a default gateway value of 255.255.255.255. D. When you check their systems, they have an IP address from the 169.254.x.x range.
| | 5: | You want to provide a mechanism by which users can securely copy files to and from a remote server. Which of the following are you most likely to use for this purpose? (Choose two.) A. SCP B. RCP C. TFTP D. SFTP
| | 6: | Which of the following IP addresses is not from a private address range? A. 192.168.200.117 B. 172.16.3.204 C. 127.45.112.16 D. 10.27.100.143
| | 7: | You have been tasked with temporarily disabling Telnet access for external users. Which is the best way to accomplish this? A. Block port 53 on the corporate firewall. B. Block port 23 on the corporate firewall. C. Uninstall the Telnet service. D. Configure ICS to ignore client-initiated Telnet requests.
| | 8: | Which of the following layer 4 protocols is used to provide connectionless service? | | 9: | Which of the following protocols provides the security for HTTPS? A. HTTP B. SSL C. Telnet D. TCP
| | 10: | Which of the following best describes the function of the default gateway? A. Provides the route for destinations outside of the local network. B. Enables a single Internet connection to be used by several users. C. Identifies the local subnet and formulates a routing table. D. Used to communicate in a multiple-platform environment.
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Answers to Exam Prep Questions| A1: | The correct answer is A. The function of ARP is to resolve IP addresses to MAC addresses. Answer B is incorrect; the responsibility for resolving NetBIOS names to IP addresses is a function of WINS or it can be achieved via broadcasts. Answer C describes the function of the RARP protocol. Resolving hostnames to IP addresses is a function of DNS; thus, answer D is incorrect. | | A2: | The correct answer is D. This is correct because the HTTP service uses port 80, so blocking port 80 will prevent users from using the HTTP service. Answer A is incorrect as DNS uses port 53; answer B is also incorrect, as POP3 uses port 110; and finally FTP (answer C) is incorrect, as it uses port 21. | | A3: | The correct answer is A. Class B addresses fall into the range 128 to 191. Therefore, answer A is the only one of the addresses listed that falls into that range. Answer B is a Class A address, and answers C and D are both Class C IP addresses. | | A4: | The correct answer is D. When a Windows XP Professional system that is configured to obtain an IP address via DHCP fails to obtain an address, it uses APIPA to assign itself an address from the 169.254.x.x address range. An address of 0.0.0.0 normally results from a system that does not support APIPA failing to get an address via DHCP. The 192.168.x.x address range is not used by APIPA. The IP address 255.255.255.255 is the broadcast address. A DHCP failure would not lead to a system assigning itself this address. | | A5: | The correct answers are A and D. The Secure Copy Protocol (SCP) uses SSH technology to ensure that authentication information and data are kept secure. The Secure File Transfer Protocol (SFTP) can also be used for that purpose. The Remote Copy Protocol (RCP) and the Trivial File Transfer Protocol (TFTP) are both considered insecure, as they do not encrypt information as it travels across the network. | | A6: | The correct answer is C. The 127.x.x.x network range is reserved for the loopback function. It is not one of the recognized private address ranges. The private address ranges as defined in RFC 1918 are 10.x.x.x, 172.16.x.x172.31.x.x, and 192.168.x.x. | | A7: | The correct answer is B. By blocking port 23, you can disable the Telnet service. Answer A is incorrect, as port 53 is used by DNS. Uninstalling the Telnet service (answer C) is not a practical solution, and D is an invalid answer. | | A8: | The correct answer is A. UDP provides connectionless service and operates at layer 4 or the transport layer of the OSI model. TCP also operates at layer 4 but provides connection-oriented service. None of the other options function at the transport layer. | | A9: | The correct answer is B. The Secure Socket Layer protocol is used to provide security for HTTPS. HTTP is a insecure version of HTTPS. Telnet is a protocol used to send or receive files from a remote system. It is not a security mechanism. TCP is a connection oriented transport protocol. It does not provide security for other protocols. | | A10: | The correct answer is A. The default gateway enables systems on one local subnet to access those on another. Answer B describes Internet Connection Sharing (ICS). None of the other answers best describe the main function of a default gateway. |
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