Networking

Question 1

What are the addressing schemes used for addressing network packets so they reach their destination?

Answer 1

1. MAC (media access control) addresses, used by hardware.
2. IPv4, IPv6 network addresses, used by software.
3. Hostnames, used by people.

Question 2

What do IP addresses identify?

Answer 2

A machines network interfaces?

Question 3

What is a port?

Answer 3

A 16 bit number that supplements IP addresses to specify a particular communication channel.

Question 4

What are the four IP address types?

Answer 4

1. Unicast: Addresses that refer to a single network interface.
2. Multicast: Addresses that simultaneously target a group of hosts.
3. Broadcast: Addresses that include all hosts on a local subnet.
4. Anycast: addresses that resolve to any one of a group of hosts.

Question 5

How many bytes are IPv4 addresses?

Answer 5

4 Bytes.

Question 6

Who sets the boundary between network and host portions of IPv4 addresses?

Answer 6

Administrator.

Question 7

In what format are IPv4 addresses written?

Answer 7

Decimal numbers, 1 for each byte.

Question 8

What decimal number is always part of the network portion in IPv4 addresses?

Answer 8

The left most number.

Question 9

How many bytes are IPv6 addresses?

Answer 9

16 Bytes.

Question 10

How many bytes are each the network and host portion in IPv6 addresses

Answer 10

8 Bytes each.

Question 11

What was IPv6 originally created for?

Answer 11

To solve the problem of IP exhaustion.

Question 12

What issues is IPv6 now being used to help solve?

Answer 12

Routing, mobility, and locality of reference.

Question 13

Describe IPv6.

Answer 13

128 bits divided into 8 groups of 16 bits each. Separated by colons. Each 16 bit group is represented by hexadecimal digits.

Question 14

What is IP spoofing?

Answer 14

When the IP address of the host from which a packet was sent has been changed/spoofed.

Question 15

Who is the victim of IP spoofing?

Answer 15

The machine identified by the spoofed source. Error and return packets can disrupt their network connections.

Question 16

What is the solution to IP spoofing

Answer 16

Block outgoing packets whose source address is not within your address space.

Question 17

What is the security issue with IP forwarding?

Answer 17

Hosts that forward packets can be coerced into compromising security by making external packets appear to have come from inside the network.

Question 18

What is the solution to issues with IP forwarding?

Answer 18

Turn off IP forwarding.

Question 19

What are the two network interfaces each system minimally has?

Answer 19

Virtual loopback interface

One real network card or port.

Question 20

What are the 4 steps in adding a new machine to a local network?

Answer 20

1. Assign a unique IP address and hostname.
2. Configure network interfaces and IP addresses.
3. Set up a default route and perhaps fancier routing.
4. Point to a DNS name server to allow access to the rest of the internet.

Question 21

What is routing?

Answer 21

The process of directing a packet through the maze of networks that stand between its source and its destination.

Question 22

Where is routing information stored?

Answer 22

In a routing table in the kernel.

Question 23

What are the two distinct things the term “routing” is commonly used for?

Answer 23

1. Looking up network addresses in the routing table as part of the process of forwarding a packet to a destination.
2. Building the routing table.

Question 24

What does DHCP stand for?

Answer 24

Dynamic Host Configuration Protocol

Question 25

What is DHCP

Answer 25

The process a device takes when connected into a network that obtains an IP address for itself on the local network, sets up an appropriate default route, and connects itself to a local DNS server.