Chapter 7 - IP Addressing

Which statement regarding private IP addresses is most accurate? Private addresses cannot be used in intranets that require routing. Private addresses must be assigned by a registrar or ISP. A remote host across the Internet cannot ping your host if it has a private address. Private addresses can only be used by a single administrative domain.

A remote host across the Internet cannot ping your host if it has a private address.

What two statements about IPv6 addresses are true? Leading zeros are required. Two colons (::) are used to represent successive hexadecimal fields of zeros. Two colons (::) are used to separate fields. A single interface will have multiple IPv6 addresses of different types.

A single interface will have multiple IPv6 addresses of different types.

In a Class C IP address, how long is the network address? 8 bits 16 bits 24 bits 32 bits

24 bits

An IPv4 addresses uses 32 bits. How many bits is an IPv6 address? 64 128 192 255

128

What two statements about IPv4 and IPv6 addresses are true? An IPv6 address is 32 bits long, represented in hexadecimal. An IPv6 address is 128 bits long, represented in decimal. An IPv4 address is 32 bits long, represented in decimal. An IPv6 address is 128 bits long, represented in hexadecimal.

An IPv6 address is 128 bits long, represented in hexadecimal. An IPv4 address is 32 bits long, represented in decimal.

Network address of all 0s

Interpreted to mean "this network or segment."

Which of the following is a Class C network address? 10.10.10.0 255.255.255.0 127.0.0.1 255.255.255.0 128.0.0.0 255.255.0.0 192.255.254.0 255.255.255.0

192.255.254.0 255.255.255.0

Which of the following is an invalid IP address for a host? 10.0.0.1 128.0.0.1 224.0.0.1 172.0.0.1

224.0.0.1

Entire IP address set to all 1s (same as 255.255.255.255)

Broadcast to all hosts on the current network; sometimes called an "all 1s broadcast" or limited broadcast.

Which of the following is a Layer 2 broadcast? FF.FF.FF.EE.EE.EE FF.FF.FF.FF.FF.FF 255.255.255.255 255.0.0.0

FF.FF.FF.FF.FF.FF

Host address of all 0s

Interpreted to mean "network address" or any host on specified network.

What is the name for a 48-bit (6-byte) numerical address physically assigned to a network interface, such as a NIC?

MAC address

Name some of the benefits of IPv6 over IPv4.

More available IP addresses, IPSec, mobility, efficiency due to less overhead in the header size, multicasts instead of broadcasts and two new types of communication: unicast and anycast.

Network 127.0.0.1

Reserved for loopback tests. Designates the local host and allows that host to send a test packet to itself without generating network traffic.

What is the 127.0.0.1 address used for?

loop-back tests

You want to ping the loopback address of your local host. Which two addresses could you type? ping 127.0.0.1 ping 0.0.0.0 ping ::1 trace 0.0.::1

ping 127.0.0.1 ping ::1

Describe the Class A range.

the first byte is assigned to the network address and the remaining bytes to the host address. This gives a possibility of 128 subnets, or networks. The first bit of the first byte (the network address) is always 0 or off. Class A addresses can range from 0 - 127 in the first byte as a result. The three remaining bytes belong to the host address. This allows for 2^24 or 16,777,216 possible host addresses. All valid host addresses in a class A range are from xxx.0.0.1 to xxx.255.255.254

Describe the Class C range.

the first three bytes are the network addresses. 24 bits minus 3 reserved positions leaves 21 positions, or 2^21 or 2,097,152 possible class C networks. Each class C address has 8 bits or 1 byte for host addresses. This gives 256 minus 2 reserved addresses (all 0s or all 1s), so 254 possible host addesses. The valid hosts would be the numbers in between the network address and the broadcast address: 192.168.100.1 through 192.168.100.254.

Which of the following is a valid Class A address? 191.10.0.1 255.0.0.0 127.10.0.1 255.0.0.0 128.10.0.1 255.0.0.0 126.10.0.1 255.0.0.0

126.10.0.1 255.0.0.0

Which of the following is a valid Class B address? 10.1.1.1 255.255.0.0 126.1.1.1 255.255.0.0 129.1.1.1 255.255.0.0 192.168.1.1 255.255.0.0

129.1.1.1 255.255.0.0

Which of the following is a valid IP address that can be used on the Internet (meaning the public addressing scheme)? 10.10.1.1 168.16.1.1 234.1.1.1 172.30.1.1

168.16.1.1

A host automatically configured with an address from which of the following ranges indicates an inability to contact a DHCP server? 169.254.0.x with a mask of 255.255.255.0 169.254.x.x with a mask of 255.255.0.0 169.254.x.x with a mask of 255.255.255.0 169.255.x.x with a mask of 255.255.0.0

169.254.x.x with a mask of 255.255.0.0

What is the private address range for class B networks?

172.16.0.0 - 172.31.255.255

Which of the following are private IP addresses? (Choose two.) 12.0.0.1 168.172.19.39 172.20.14.36 172.33.194.30 192.168.24.43

172.20.14.36

Which of the following addresses is not allowed on the Internet? 191.192.168.1 191.168.169.254 172.32.255.0 172.31.12.251

172.31.12.251

What is the valid range used for a class C private IP address?

192.168.0.0 - 192.168.255.255

What is the term for the auto-configuration technology responsible for addresses that start with 169.254?

APIPA

What defines a multicast address?

Again, as in IPv4, packets addressed to a multicast address are delivered to all interfaces identified by the multicast address. Sometimes people call them one-to-many addresses. It's really easy to spot multicast addresses in IPv6 because they always start with FF.

Which of the following describes a broadcast address? All network bits are on (1s). All host bits are on (1s). All network bits are off (0s). All host bits are off (0s).

All host bits are on (1s).

State why we need IPv6.

IPv4 only gives us a possible theoritical limit of 4.3 billion addresses but in reality there are only about 250 million addresses available. CIDR and NAT has helped prevent reaching this limit for a while but there is now an immediate need for more addresses. IPv6 gives a possible limit of 3.4 x 10^38 addresses. IPv6 packets also have less overhead at 64 bits for the header compared to IPv4's headers which have 20 bytes, or 160 bits.

Describe link-local.

IPv4 uses 169. 254.0.1 - 169.254.254.255 inclusive for link-local addresses. IPv6 uses fe80::/64 range for link-local addresses. Machines assign link-local addresses to themselves, at random using these ranges. Machines assign link-local addresses to themselves if they haven't been set up with a static IP address or automatically configured by a DHCP server on the network.

Describe IPv6 addressing.

IPv6 addresses are 128 bits. IPv6 addresses are eight groups of hexadecimal quartets. Any four group of zeroes may be shortened to one zero for that quartet.

What gives IPv6 the ability to reference more addresses than IPv4?

IPv6 has a lot more address space to offer addresses. IPv4 only has the potential for approx. 4 billion addresses while IPv6 can offer up to 3.4 x 10^34 addresses.

Host address of all 1s

Interpreted to mean "all hosts" on the specified network; for example, 128.2.255.255 means "all hosts" on network 128.2 (Class B address).

Network address of all 1s

Interpreted to mean "all networks."

What defines a unicast address?

Packets addressed to a unicast address are delivered to a single interface, same as in IPv4. For load balancing, multiple interfaces can use the same address.

Which of the following is true when describing a unicast address? Packets addressed to a unicast address are delivered to a single interface. These are your typical publicly routable addresses, just like regular publicly routable addresses in IPv4. These are like private addresses in IPv4 in that they are not meant to be routed. These addresses are meant for nonrouting purposes, but they are almost globally unique so it is unlikely they will have an address overlap.

Packets addressed to a unicast address are delivered to a single interface.

Which of the following is true when describing a multicast address? Packets addressed to a unicast address from a multicast address are delivered to a single interface. Packets are delivered to all interfaces identified by the address. This is also called a one-to-many address. It identifies multiple interfaces and is delivered to only one address. This address can also be called one-to-one-of-many. These addresses are meant for nonrouting purposes, but they are almost globally unique so it is unlikely they will have an address overlap.

Packets are delivered to all interfaces identified by the address. This is also called a one-to-many address.

Describe the private IP ranges.

Private class A: 10.0.0.0 - 10.255.255.255 Private class B: 172.16.0.0 - 172.31.255.255 Private class C: 192.168.0.0 - 192.168.255.255

What is the Class C range of values for the first octet in decimal and in binary?

The first two bits have to be turned on and the third bit has to be turned off, so the range is 192 - 223.

A host is rebooted and you view the IP address that it was assigned. The address is 169.123.13.34. Which of the following happened? The host received an APIPA address. The host received a multicast address. The host received a public address. The host received a private address.

The host received an APIPA address.

Describe unique local.

These addresses are also intended for nonrouting purposes, but they are nearly globally unique, so it's unlikely you'll ever have one of them overlap with any other address. Unique local addresses were designed to replace site-local addresses, so they basically do almost exactly what IPv4 private addresses do—allow communication throughout a site while being routable to multiple local networks. The difference between link-local and unique local is that unique local can be routed within your organization or company.

Which of the following is true when describing an anycast address? Packets addressed to a unicast address from an anycast address are delivered to a single interface. Packets are delivered to all interfaces identified by the address. This is also called a one-to-many address. This address identifies multiple interfaces, and the anycast packet is delivered to only one address. This address can also be called one-to-one-of-many. These addresses are meant for nonrouting purposes, but they are almost globally unique so it is unlikely they will have an address overlap.

This address identifies multiple interfaces, and the anycast packet is delivered to only one address. This address can also be called one-to-one-of-many.

Entire IP address set to all 0s

Used by Cisco routers to designate the default route. Could also mean "any network."

Describe the APIPA range.

hosts - 169.254.0.1 - 169.254.255.254 The client will configure itself with a subnet mask of 255.255.0.0.

Describe the Class B range.

the first two bytes are assigned to network addressing and the last bytes are assigned to host addressing. The first bit of the first byte must always be 1 and the second bit of the first byte must always be turned off or 0. Therefore, the network addressing range in the first byte can be from 128 to 191. Since the first and second bits of the first byte must always be 1, then 0, instead of 2^16 possible subnet combinations there are 2^14 combinations. This is because there are 14 bits to manipulate, not 16. There are (2^16) -2 possible host addresses ("-2" accounts for the all 0s or all 1s combo). All valid host addresses in a class B range are from xxx.xxx.0.1 - xxx.xxx.255.254.