Ch20-DHCP and Multicast Flashcards

1
Q

Any device that uses DHCP protocols to ask to lease an IP address from a DHCP server, or learn and IP settings from that server

A

DHCP client

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2
Q

The name of the router IOS feature that forwards DHCP messages from clients to servers by changing the destination IP address from 255.255.255.255 to the IP address of the DHCP server

A

DHCP relay agent

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3
Q

Software that waits for DHCP clients to request to least DHCP addresses as well as listing other important IP settings for the client

A

DHCP server

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4
Q

IPv4 address 255.255.255.255. A packet sent to this address is sent as a data-link broadcast, but only flows to hosts in the subnet into which it was originally sent. Routers do not forward these packets

A

Local broadcast address

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5
Q

Specifically, the largest numeric address in a subnet, designed so that packets sent to this address should be delivered to all hosts in that subnet

A

subnet broadcast address

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6
Q

A special address in each class full network that can be used to broadcast a packet to all hosts in that same glassful network.

A

network broadcast address

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7
Q

A class D IPv4 address. When used as a destination address in a packet, routers collectively work to deliver copies of the one original packet to all hosts that have previously registered to receive packets sent to that particular address

A

multicast address

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8
Q

Command reference: Global command that reserves and inclusive range of addresses so that the DHCP server function does no least out the specified addresses

A

ip DHCP excluded-address first last

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9
Q

Command reference: Creates a pool, by name, and moves the user to DHCP server pool configuration mode

A

ip dhcp pool pool-name

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10
Q

Command reference: DHCP pool mode subcommand that defines a network or subnet causing the DHCP server to lease out addresses in that subnet

A

network subnet-id [ddn-mask | prefix}

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11
Q

Command reference: DHCP pool mode subcommand that defines one or more routers as default routers, with that information passed on to clients served by this pool

A

default-router address1 address2…

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12
Q

Command reference: DHCP pool mode subcommand that defines the list of DNS servers to be used by clients served by this pool.

A

dns-server address1 address2…

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13
Q

Command reference: DHCP pool mode subcommand that defines the length allowed for a DHCP lease for clients served by this pool.

A

lease days hours minutes

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14
Q

Command reference: Interface subcommand that tells the router to notice local subnet broadcasts that use UDP, and change the source and destination IP address, enabling DHCP servers to sit on a remote subnet

A

ip helper-address ip-address

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15
Q

Command reference: Lists the router’s IPv4 address table

A

show arp show ip arp

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16
Q

Command reference: Lists the currently leased IP addresses on a DHCP server, along with the client identifier and lease time information

A

show ip dhcp binding

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17
Q

Command reference: Lists the configured range of addresses in the pool, along with usage statistics and utilization high-low watermarks

A

show ip dhcp server statistics

18
Q

Command reference: Lists IP addresses that the server found were already in use when the server tried to lease an address to a host

A

show ip dhcp conflict

19
Q

Command reference: Removes all entries from the DHCP server’s conflict list

A

clear ip dhcp conflict

20
Q

Command reference: On a host, lists IP settings for NIC interfaces

A

ifconfig ipconfig

21
Q

Command reference: On a host, lists the hosts routing table, often listing the default router with a route to 0.0.0.0

A

netstat -rn

22
Q

Command reference: On a host, lists the host’s ARP table

A

arp -a

23
Q

What command produced the following output?

A

show ip dhcp pool

24
Q

What command produced the following output?

A

show ip dhcp binding

25
Q

What is the purpose of the reserved IP address 0.0.0.0?

A

Used as a source IP address by clients that have not yet obtained an IP address

26
Q

What is the purpose of the reserved address 255.255.255.255?

A

Local broadcast address. Packets sent to this address are broadcast to all nodes on the local link, but will not be forwarded by routers.

27
Q

A router interface was configured with the ip helper-address command. Once configured, what will the router do with that interface?

A
  1. Watch for incoming DHCP messages (or UDP messages) with a destination address of 255.255.255.255
  2. Change the source IP address of the message packet to the IP address of the incoming interface.
  3. Change the destination IP address of the message packet to the IP address defined by the ip-helper command.
  4. Route the packet to the destination.
28
Q

What information is provided by the show ip dhcp binding command?

A
  • state information about each leased address
    • IP address
    • Client ID/hardware address
    • Lease expiry
    • Allocation method
      • static
      • dynamic
      • automatic
29
Q

What information is provided by the show ip dhcp pool command?

A
  • Lists configured range of addresses and stats for the pool
    • utlization
    • total addresses
    • total leased
    • next issue
30
Q

What address is reserved for the local broadcast address?

A

255.255.255.255

31
Q

What is another name for the local broadcast address?

A

Limited broadcast

32
Q

A host device sends a local broadcast to all other nodes. What happens when the broadcast reaches a local router?

A

The router will filter the broadcast, preventing it from reaching other networks.

33
Q

What is the subnet broadcast address?

A

The numberically highest address in the subnet.

34
Q

Packets sent to a subnet broadcast address can be routable. Once reaching the target network router interface, how does the router handle the broadcast?

A

Sends the broadcast as a data-link broadcast on the local-link, reaching all other hosts in the subnet.

35
Q

What are other names for a broadcast message sent to the subnet broadcast address?

A

directed broadcast

all-hosts broadcast

36
Q

What is the network broadcast address?

A

Numerically highest address in the classful network in question.

37
Q

What is another name for the “all-subnets” broadcast address?

A

Network broadcast address

38
Q

What is the range of address space for multicast groups?

A

Class D address space (224-239 in the first octet)

39
Q

What type of address is typcially used by common applications?

A

unicast

40
Q

What type of addresses are described by Class A,B, or C addressing?

A

unicast

41
Q

What type of addresses are commonly used by “overhead” protocols?

A

broadcast

42
Q

What types of addresses are required to be used as destination addresses only?

A

broadcast and multicast