CIS 3580 - Chapter 11
Well-known IPv6 Multicast address
A pre-defined IPv6 multicast address used to reach a group of devices running a common protocol or service
variable-length subnet masking (VLSM)
A process that makes it possible to specify a different subnet mask for the same network number on different subnets. VLSM can help optimize available address space.
Router Advertisement (RA) Message
An ICMPv6 message sent by a router to provide addressing information to hosts using SLAAC
Global Routing Prefix
An IPv6 prefix, or network, portion of an address that is assigned by the provider, such as an ISP, to a customer or site
Link-local address (LLA)
An LLA is required for every IPv6-enabled device. LLAs are used to communicate with other devices on the same local link. With IPv6, the term link refers to a subnet. An LLA is confined to a single link. The uniqueness of an LLA must only be confirmed on that link because LLAs are not routable beyond the link. In other words, routers do not forward packets with link-local source or destination
DMZ (Demilitarized Zone)
An area of an internal network where resources are available to the internet, such as a web server, and where devices have IPv6 addresses and public IPv4 addresses accessible through the internet.
Which of the following are components of an IPv4 address? (Choose two) A) Subnet Portion B) Network Portion C) Logical Portion D) Host Portion E) Physical Portion F) Broadcast Portion
B and D The two portions of an IPv4 address are the network portion and the host portion, as determined by the subnet mask
Preferred format
The IPv6 address format x:x:x:x:x:x:x:x, with each x consisting of four hexadecimal values
Solicited-node multicast address
The IPv6 multicast address associated with an IPv6 unicast address that is mapped to a special ethernet multicast address
Interface ID
The host portion of an IPv6 global unicast address. This is the individual host IP portion. It can be assigned to one interface or more than one interface, depending on the type of IPv6 address.
Octet Boundary
The part of an IPv4 address that falls between octets
If a network device has a mask of /30, how many IPv4 addresses are available for hosts on this network? A) 64 B) 8 C) 2 D) 32 E) 16 F) 4
C A /30 prefix length means 30 1 bits indicating the network portion of the address, which leaves 2 bits for the host portion. 2^2 -2 bits (for the network and broadcast addresses) equals 2 valid host addresses
What subnet mask is represented by the slash notation /20? A) 255.255.255.248 B) 255.255.224.0 C) 255.255.240.0 D) 255.255.255.0 E) 255.255.255.192
C /20 is 20 continuous 1 bits, calculated as follows: 255 = 8 1 bits 255 = 8 1 bits 240 = 4 1 bits 0 = 0 1 bits Total = 20 1 bits
What is the prefix length notation for the subnet mask 255.255.255.224? A) /25 B) /26 C) /27 D) /28
C 255.255.255.224 contains 27 continuous 1 bits
Which subnet mask would be used if 5 host bits are available? A) 255.255.255.0 B) 255.255.255.128 C) 255.255.255.224 D) 255.255.255.240
C 255.255.255.224, or /27, contains 27 continuous 1 bits. This leaves 5 bits for host addresses
Which subnet mask would be used if exactly 4 host bits are available? A) 255.255.255.224 B) 255.255.255.128 C) 255.255.255.240 D) 255.255.255.248
C 255.255.255.240 is 28 continuous 1 bits. This leaves 4 host bits.
What does the IPv4 address 172.17.4.250/24 represent? A) Network Address B) Multicast Address C) Host Address D) Broadcast Address
C An AND operation between the IPv4 address 172.17.4.250 and subnet mask 255.255.255.0 (/24), results in a network address of 172.17.4.0 (all 0 bits in the host portion). The broadcast address for this network is 172.17.4.255 (all 1 bits in in the host portion). This means 172.17.4.250 is neither a network address nor a broadcast address and is therefore a host address
What is the purpose of the subnet mask in conjunction with an IPv4 address? A) to uniquely identify a host on a network B) to identify whether the address is public or private C) to determine the subnet to which the host belongs D) to mask the IP address to outsiders
C The ANDing process is used between an IPv4 address and its subnet mask to determine the network address for that device
How many usable IPv4 addresses are available on the 192.168.1.0/27 network? A) 256 B) 254 C) 62 D) 30 E) 16 F) 32
D A network address with a /27 prefix length contains 27 continuous 1 bits. This leaves 5 bits for host addresses, or 2^5 - 2 (for the network and broadcast address), which equals 30 valid hosts addresses
Which address type is not supported in IPv6? A) Private B) multicast C) Unicast D) Broadcast
D IPv6 does not have a broadcast. IPv6 does include an all-IPv6-device multicast address
Why does a Layer 3 device perform the ANDing process on a destination IPv4 address and subnet mask? A) to identify the broadcast address of the destination network B) to identify the host address of the destination host C) to identify faulty frames D) to identify the network address of the destination network
D The ANDing process on an IPv4 address and the subnet mask determines the network portion of an address
Subnet ID
Part of the IPv6 global unicast address used by an organization to identify subnets within its site. The larger the subnet ID, the more subnets available. The subnet ID field is the area between the global routing prefix and the interface ID. Unlike IPv4, where you must borrow bits from the host portion to create subnets, IPv6 was designed with subnetting in mind. An organization used the subnet ID to identify subnets within its site.
What is the purpose of the command ping ::1? A) It tests the internal configuration of an IPv6 host B) It tests the broadcast capability of all hosts on the subnet C) It tests the multicast connectivity to all hosts on the subnet D) It tests the reachability of the default gateway for the network
A ::1 is an IPv6 loopback address. Pinging a loopback address helps verify the internal configuration of IP on the host
At a minimum, which address is required on IPv6-enabled interfaces? A) link-local B) Unique local C) Site local D) global unicast
A For any device to be enabled for IPv6, the interface must have a link-local address
What is the most compressed format possible for the IPv6 address 2001:0db8:0000:ab00:0000:0000:0000:1234? A) 2001:db8:0:ab00::1234 B) 2001:db8:0:ab::1234 C) 2001:db8:0000:ab::1234 D) 2001:db8:0:ab:0::1234
A Leading 0s are omitted, and a single contiguous string of all-0 hextets can be replaced with a double colon (::)
What is the minimum configuration for a router interface that is enabled for IPv6? A) To have a link-local IPv6 address B) To have both IPv4 and IPv6 addresses C) to have a self-generated loopback D) To have both a link-local address and a global unicast address E) to have only an automatically generated multicast address
A Like any other IPv6 device, a Cisco router's interface must have a link-local address to be enabled for the IPv6. It does not have to have a global unicast address, but it must have a link-local address.
Transmission Control Protocol (TCP)
A Layer 4 protocol of the TCP/IP model that lets applications guarantee delivery of data across a network
Stateless Address Autoconfiguration (SLAAC)
A plug-and-play IPv6 feature that enables devices to connect themselves to the network without any configuration and without any servers (like DHCP servers)
Intranet
A private connection of LANs and WANs that belongs to an organization and that is designed to be accessible only by the organization's members, employees, or others with authorization.
Network Address Translation 64 (NAT64)
A technique that allows IPv6- enabled devices to communicate with IPv4-enabled devices using a translation technique similar to NAT for IPv4. An IPv6 packet is translated to an IPv4 packet and vice versa
Stateless DHCPv6
A type of DHCP that provides information other than the IPv6 address and prefix length, such as DNS server and domain name. It does not provide a default gateway address
Router Solicitation (RS) message
An ICMPv6 message sent by devices to request and ICMPv6 Router advertisement message
Dual Stack
An IPv4-to-IPv6 transition method that runs both IPv4 and IPv6 on networking devices. A type of network that supports both IPv4 and IPv6 traffic.
Global Unicast Address (GUA)
An IPv6 address similar to a public IPv4 address. It is globally unique, internet-routable address. Global unicast address can be configured statically or assigned dynamically.
What is the most compressed representation of the IPv6 address 2001:0db8:0000:abcd:0000:0000:0000:0001? A) 2001:0db8:abcd::1 B) 2001:db8:0:abcd::1 C)2001:0db8:abcd::1 D) 2001:0db8:0000:abcd::1 E) 2001:db8::abcd:0:1
B Leading 0s are omitted, and a single contiguous string of all-0 hectets can be replaces with a double colon (::)
Which type of IPv6 address is not routable and is used only for communication on a single subnet? A) Global unicast address B) Link-local address C) Loopback address D) Unique local address E) Unspecified address
B Link-local address are only for communications on the local link or network and are not routable off that link
Which statement is true about variable-length subnet masking? A) All the subnets are equally sized. B) The sizes of subnets may be different, depending on requirements. C) Subnets may only be subnetted on additional time. D) Bits are returned, rather than borrowed, to create additional subnets.
B VLSM allows for the option to subnet any subnet further as long as there are enough host bits to do so. This makes possible a variety of sizes of subnets or networks.
What type of address is automatically assigned to an interface when IPv6 is enabled on that interface? A) Global unicast B) Link-local C) Loopback D) Unique local
B When a device is enabled for IPv4 on an interface, that interface automatically assigns itself a link-local address. Most host operating systems - including Windows, macOS, Linux, iOS, and Android - have both and IPv6 installed by default. This means they have, at minimum, an IPv6 link-local address
Your organization is issued the IPv6 prefix 2001:0:130f::/48 by your service provider. With this prefix, how many bits are available for your organization to create /64 subnetworks of interface ID bits are not borrowed? A) 8 B) 16 C) 80 D) 128
B With a /48 global routing prefix and a /64 prefix length, you are left with 16 bits between the global routing prefix and interface ID for the subnet ID. Subtracting 48 (global routing prefix) from 64 (the prefix length) yields the subnet ID
Which IPv6 network prefix is only intended for local links and can not be routed? A) 2001::/3 B) fc00::/7 C) fe80::/10 D) ff00::/12
C Link-local address are only for communications on the local link or network and are not routable off that link
What is the prefix associated with the IPv6 address 2001:db8:d15:ea:cc44::1/64? A) 2001::/64 B) 2001:db8::/64 C) 2001:db8:d15:ea::/64 D) 2001:db8:d15:ea:cc44::/64
C With a /64 prefix length, the first 64 (or first 4 hextets) - in this case 2001:db8:d15:ea - indicate the network address
What is the interface ID of the IPv6 address 2001:db8::1000:a9cd:47ff:fe57:fe94/64? A) fe94 B) fe57:fe94 C) 47ff:fe57:fe94 D) a9cd:47ff:fe57:fe94 E) 1000:a9cd:47ff:fe57:fe94
D A /64 prefix length indicates that the first 64 bits, 2001:db8::1000, indicate the network address. This leaves 64 bits for the interface ID (or 4 hextets): a9cd:47ff:fe57:fe94
How many valid host addresses are available on an IPv4 subnet that is configured with a /26 mask? A) 254 B) 190 C) 192 D) 62 E) 64
D A /26 mask means 26 1 bits indicating the network portion of the address, which leaves 6 bits for the host portion. 2^6 - 2 bits (for the network and broadcast addresses) equals 62 valid host address
A network administrator is variably subnetting a network. The smallest subnet has a mask of 255.255.255.224. How many usable host addresses will this subnet provide? A) 2 B) 6 C) 14 D) 30 E) 62
D The 255.255.255.224 subnet mask or a /27 prefix length results in 28 continuous 1 bits, which indicates the network portion of the address. This leaves 5 bits for the host portion. 2^5 - 2 bits (for the network and broadcast address) equals 30 valid host address.
What is the network address for the IPv6 address 2001:db8:aa04:b5::1/64? A) 2001::/64 B) 2001:db8::/64 C) 2001:db8:aa04:::/64 D) 2001:db8:aa
D With a /64 prefix lenth, the first 64 bits (or first 4 hextets) - in this case, 2001:db8:aa04:b5 - indicates the network address
What is indicated by a successful ping to the ::1 IPv6 address? A) The host is cabled correctly B) The default gateway address is configured correctly C) All hosts on the local link are available D) The link-local address is correctly configured E) IP is properly installed on the host
E Pinging a loopback address verifies that IP is working on the local host. Most host operating systems - including Windows, macOS, Linux, iOS, and Android - have both IPv4 and IPv6 installed by default
Extended Unique Identifier (EUI)
EUI-64 A process for creating an IPv4 interface ID by using 48-bit Ethernet MAC address, inserting fffe in the middle, flipping the seventh bit
If a network device has a mask of /28, how many IP addresses are available for hosts on this network? A) 256 B) 254 C) 62 D) 32 E) 16 F) 14
F A /28 prefix length means 28 continuous 1 bits, which indicates the network portion of the address. This leaves 4 bits for the host portion. 2^4 - 2 bits (for the network and broadcast address) equals 14 valid host addresses
Stateful DHCPv6
Similar to DHCP for IPv4, a type of DHCP that provides IPv6 address, prefix length, and other information, such as the DNS server and domain name. It does not provide a default gateway address
Tunneling
The process of encapsulating an IP packet inside another IP packet
What are the three parts of an IPv6 global unicast address? (Choose three) A) An interface ID that is used to identify the local network for a particular host B) A global routing routing prefix that is used to identify the network portion of the address that has been provided by the ISP C) A subnet ID that is used to identify networks inside the local enterprise site D) A global routing prefix that is used to identify the portion of the network address provided by a local administrator E) An interface ID that is used to identify the local host on the network
B, C, and E An IPv6 GUA has three parts: (1) the global routing prefix allocated by the ISP or provider of the IPv6 address; (2) a subnet ID, which is the bits between the global routing prefix and the interface ID; (3) The interface ID, which is typically 64 bits and is highly recommended for compatibility with SLAAC
A network administrator subnets the 192.168.10.0/24 network into subnets with /26 masks. How many equal-sized subnets are created? A) 1 B) 2 C) 4 D) 8 E) 16 F) 64
C A 192.168.10.0/24 network subnetted using a /26 prefix extends the subnet mask 2 bits, from /24 to /26. 2^2 = 4 subnets
Octet
A group of 8 binary bits. It is similar to, but not the same as, a byte. One application in computer networking is to use octets to divide IPv4 addresses into 4 components