Networking Chapter 5

A computer is unable to communicate with other computers on the network. You use ipconfig and see the following information: IP address: 169.254.5.7 Subnet mask: 255.255.0.0 Default gateway: blank DNS server: blank A. A DHCP server can't be reached. B. The default gateway needs to be manually configured. C. The DNS server IP address needs to be manually configured. D. None of the above

A An address starting with 169.254 is an APIPA address. An APIPA address is assigned to DHCP clients when a DHCP server can't be reached. Manually configuring the default gateway or the DNS server IP address isn't needed for a DHCP client.

Which of the following addresses is a valid IPv4 address A. 192.168.1.256 B. 10.1.25.2 C. 2001:0000:4137:9e76:3c2b:05ad:3f57:fe98 D. 2001:0000:4137:9g76:3c2b:05zd:3x57:gh98

B IPv4 addresses are in dotted decimal format. Each decimal must be between 0 and 255. You cannot use 256, since 256 is not a valid number in an IPv4 address.

Which of the following IP addresses is in one of the reserved IP address ranges defined by RFC 1918 A. 10.80.256.1 B. 172.17.34.14 C. 192.169.4.5 D. 224.17.2.5

B The reserved IP address ranges are as follows: 10.0.0.1 through 10.255.255.254 172.16.0.1 through 172.31.255.254 192.168.1.1 through 192.168.255.254

What is the subnet mask for the following IP address: 192.168.1.5 /26 A. 192.168.1.5 B. 255.255.255.0 C. 255.255.255.192 D. 255.255.255.240

C The /26 in the IP address is CIDR notation indicating how many bits are a 1 in the subnet mask. The first octet has eight 1s, the second octet has eight 1s, the third octet has eight 1s, and the fourth octet has two 1s. The subnet mask is 255.255.255.192.

What class is the following IP address: 192.168.1.5 A. Class A B. Class B C. Class C D. Class D

C The first decimal in a Class C address is in the range of 192-224

How many hosts are supported in subnet with a network ID of 192.168.1.128 /26 A. 30 B. 32 C. 62 D. 64

C The formula is 2h - 2 where h is the number of bits used in the host ID. Since 26 bits are used in the network ID, 6 bits are left for the host ID (32 - 26 = 6) and 26 - 2 = 62.

True or false. The following two classless IP addresses have the same network ID: 192.168.1.105 /26 and 192.168.1.136 /26.

False The first IP address has a subnet mask of 255.255.255.192 and a network ID of 192.168.1.64. The second IP address has a subnet mask of 255.255.255.192 and a network ID of 192.168.1.128.

True or false. The following two classful IP addresses have the same network ID: 192.168.1.5 and 192.168.2.6

False The first one has a network ID of 192.168.1.0, and the second one has a network ID of 192.168.2.0.

True or false. The following two classful IP addresses have the same network ID: 10.80.4.2 and 10.81.15.2

True Both have a network ID of 10.0.0.0.