Network

Question 1

What does transport layer do

Answer 1

communication between processes

Question 2

Network layer do?

Answer 2

communication between machines

possibly different or multiple networks

Question 3

datalink layer do?

Answer 3

communication between machines on same network

Question 4

what do routers do

Answer 4

direct traffic using logical addresses

move traffic between different networks

uses routing protocols to determine best path to send traffic

Question 5

Packet Filters

Answer 5

restricts availability of network resources to endpoint devices that comply with the organization’s security policy

Question 6

Firewall

Answer 6

Hardware, software that prevents unauthorized access to/from internal network

Question 7

Firewall: Packet filter

Answer 7

applies rules to each incoming and outgoing IP packet

forwards or discards packet based on rules match

Question 8

Firewall: Stateful-inspection

Answer 8

maintains a state table to keep track of all open connections through a firewall

Question 9

Firewall: Application-level gateway

Answer 9

Acts as a relay of application level traffic

Question 10

Firewall: Circuit level gateway

Answer 10

sets up 2 TCP connections (itself and TCP user) (itself and outside host)

relays TCP segments from one connection without examining contents

Question 11

NAT (Network Address Translation)

Answer 11

translate between private and public addresses