Comptia Network+ (N10-006) Part 3: Introduction To Ip Addressing And Binary

Front 1

How many octets are in an IP address?

Back 1

Four

Front 2

What comprises an octet in an IP address?

Back 2

A three-digit decimal number (between 0 and 255), or an eight-digit binary number.

Hint 2

Binary decimal

Front 3

What does the acronym ARP mean, and what does it do?

Back 3

Address Resolution Protocol; resolves MAC addresses from IP addresses

Hint 3

Location protocol

Front 4

What are ARP requests, and what type of communication is used when sending one?

Back 4

It is a communication to the network requesting a computer's MAC address. Broadcast communication.

Front 5

What command is used to view the ARP table on a computer?

Back 5

arp -a

Front 6

What are the various names (by OS) for a router in IP addressing?

Back 6

MAC: Router

Win: Default Gateway

Linux: Default Router

Front 7

What comprises a Subnet Mask?

Back 7

In binary form, a series of ones, followed by a series of zeroes. NEVER mixed.

Hint 7

Segregation is the rule

Front 8

What is the purpose of a Subnet Mask?

Back 8

It defines a network by separating the Network ID and Host ID.

Front 9

What is the first section of a Subnet Mask, and how is it defined?

Back 9

The Network ID; leading ones

Hint 9

Segregation

Front 10

What is the second section of a Subnet Mask, and how is it defined?

Back 10

The Host ID; trailing zeroes

Hint 10

Segregation

Front 11

What two numbers are never used in an IP address?

Back 11

255 and 0

Front 12

How is a particular network ID represented?

Back 12

The decimal equivalent of the subnet mask.

Front 13

What is different about an ARP for an IP address that isn't part of the network (as defined by the Subnet Mask)?

Back 13

The ARP requests the MAC address for the Default Gateway, rather than the IP address.

Front 14

What's another way to describe a Subnet Mask, not using the decimal IP address format, including an example?

Back 14

'Whack' or 'slash', followed by the number of ones in the mask: /24 for 255.255.255.0

Hint 14

Bit count

Front 15

What are the only numbers that can occur in each octet of a Subnet Mask, and why?

Back 15

128, 192, 224, 240, 248, 252, 254, and 255. They are the only numbers produced by adding each of the binary equivalents of 11111111 and numbers created by replacing zeroes, right to left.

Hint 15

Leading ones

Front 16

What is a class A IP address?

Back 16

Any address whose first octet is between 1(00000001) and 126 (01111110).

Front 17

What is a class B IP address?

Back 17

Any address whose first octet is between 128 (10000000) and 191 (10111111).

Front 18

What is a class C IP address?

Back 18

Any address whose first octet is between 192 (11000000) and 223 (11011111).

Front 19

What's a good shortcut for remembering classful licensing parameters, using the first octet?

Back 19

-Class A: Octet begins with zero, EXCEPT 127 (01111111)

-Class B: Octet begins with 10

-Class C: Octet begins with 110

-Class D: Octet begins with 1110

-Class E: Octet begins with 1111

Hint 19

Bits

Front 20

What is CIDR?

Back 20

Classless Interdomain Routing, or classless subnetting. It is used to create subnets within a domain.

Front 21

How are available IP addresses calculated for CIDR?

Back 21

2^n-2, where n=number of bits in the Host ID of THE LAST OCTET. (Less 2 because 0 nor 255 can be used as an IP address.)

Hint 21

Host ID

Front 22

How are the available subnets calculated for CIDR?

Back 22

2^n, where n=number of bits in the Host ID section of the subnet mask.

Hint 22

Host ID of Subnet Mask

Front 23

How are the available hosts of a subnet calculated for CIDR?

Back 23

2^n-2, where n=number of bits required to meet the host count requirement.

Hint 23

Host ID of Subnet Mask

Front 24

What are the differences and advantages of static and dynamic IP addressing?

Back 24

Static addresses are manually assigned. Dynamic addresses are automatically assigned by a DHCP server. Static requires less network overhead; dynamic requires far less administration.

Front 25

What packets are transferred between a DHCP server and a new client on the network, and how does each (client/server) respond?

Back 25

-Client broadcasts DHCPDISCOVER packet for server.

-Server compares network with scope, broadcasts available IP from scope via DHCPOFFER (ports 67 and 68).

-Client broadcasts acceptance via DHCPREQUEST.

-Server broadcasts ack via DHCPACK.

-Client initializes TCP/IP suite.

Front 26

What must be configured on a DHCP server?

Back 26

Subnet mask; IP address of the DHCP server (usually ending with .1); IP range (a.k.a. starting IP and maximum clients); and lease duration.

Front 27

What optional configurations are there on a DHCP server?

Back 27

Reserved (statically assigned) IP addresses (exclusions), Default Gateway, Domain name, DNS server(s).

Front 28

What is DHCP Relay?

Back 28

Allows a single DHCP server to serve more than one broadcast domain.

Hint 28

Broadcast

Front 29

What is the main symptom of a DHCP issue?

Back 29

Unavailability of network resources, especially Internet.

Hint 29

Resources

Front 30

What is APIPA?

Back 30

Automatic Private IP Addressing. It's an IP address used by a client if a DHCP server is unavailable.

Front 31

What is an APIPA address?

Back 31

Any IP address beginning with 169.254.

Front 32

Where does the issue reside when getting an APIPA address?

Back 32

Layer 1 or the DHCP Server itself.

Front 33

What causes a valid IP address that is outside of the domain's subnet mask?

Back 33

Rogue DHCP server.

Front 34

What is a loopback IP address?

Back 34

127.0.0.1

Front 35

What are private IP addresses?

Back 35

Meant for private networks (behind a router), not for Internet connectivity.

Hint 35

Internet

Front 36

What are private IP address ranges?

Back 36

10.x.x.x (/8)

172.16.x.x - 172.31.x.x (/12)

192.168.x.x (/16)

Front 37

What is a routing table?

Back 37

It's used by a router to keep track of the networks connected to it.

Front 38

What information is stored in a routing table, and how is it used?

Back 38

For each network: network address (0 as the last octet(s), based on subnet); subnet mask of that network; gateway (0.0.0.0 if it's a directly-connected network); and interface (the router's IP address for that network); and the metric (used to prioritize default routes).

Front 39

What is the default route in a routing table?

Back 39

Used for any IP for a network not directly connected. Address and subnet are zeros; while the Gateway is for the router on the other side of the home network. Interface is the outbound port's IP address. The lower the metric, the higher priority.

Front 40

How are port numbers used?

Back 40

Identifies data type.

Front 41

What are Well Known Ports?

Back 41

The first 1024 (0 - 1023) port numbers, used for specific applications.

Front 42

What is the format of an ephemeral port use, and what is its use?

Back 42

A sequenced number above 1024, identifying the source application. It is generated by the client.

Front 43

What is NAT, and what does it do?

Back 43

Network Address Translation. It's used by routers to transmit data between clients on the local network and the Internet, by replacing the source IP address with its own, and keeping track of the transfers.

Front 44

What are the versions of NAT, and how do they work?

Back 44

-PAT translates internal IP addresses to an Internet address and tracks packets.

-Static NAT (SNAT or port forwarding) sends specific traffic to one internal IP address.

-Dynamic NAT (DNAT or pooled NAT) assigns fixed Internet addresses (from a pool) to a specific client.

Front 45

What is port triggering and how is it implemented?

Back 45

Opens a network to accept other port numbers (different from outgoing) from incoming connections. FTP (outgoing port 21; incoming port 21) is an example.

Front 46

What are the methods for exposing internal devices to the Internet?

Back 46

Port (or Port Range) Forwarding, Port Triggering, and DMZ. (DMZ is full exposure, the other three are port-specific.)

Front 47

What is taken into consideration when creating dynamic routing tables?

Back 47

MTU (Maximum Transmission Unit) and bandwidth.

Front 48

What two types of dynamic routing protocols exist?

Back 48

Distance Vector (routing tables sent at intervals) or Link State (routing table changes are advertised as they occur).

Front 49

What are the main points of RIP (Routing Information Protocol)?

Back 49

Distance Vector, Interior Gateway protocol, used mostly in small networks. Uses hop counts to determine routes/metrics. Limited to 15 hops, and only Classful networks.

Front 50

What are the main points of OSPF (Open Shortest Path First)?

Back 50

Link State, Interior Gateway protocol. Uses Area IDs (similar to IP addresses). Converges quickly.

Front 51

What are the main points of BGP (Border Gateway Protocol)?

Back 51

Hybrid Distance Vector/Link State protocol. Exterior Gateway.

Front 52

How does BGP work?

Back 52

Breaks the Internet down into Autonomous Systems (AS). An AS is a group of one or more router networks under the control of a single entity.

Front 53

What are the main points of Autonomous Systems (AS)?

Back 53

Each has a 32-bit AS number. Internal routers only need to know their BGP router, the BGP router uses the AS number to route data correctly.