routing

Question 1

What standard is Ethernet?

Answer 1

IEEE 802.3

Question 2

What layer of the OSI model do ethernet frames operate on?

Answer 2

data link

Question 3

What do the ethernet frames contain?

Answer 3

Source and dest MAC address.

Question 4

What are sniffers?

Answer 4

Listening to all network traffic even if it isn’t intended for you. This can happen when the NIC runs in promiscuous mode.

Question 5

What is CSMA/CD?

Answer 5

Carrier sense multiple access /collision detection

Question 6

What is carrier sense?

Answer 6

computer analyzing wire before sending frame

Question 7

What is a collision domain?

Answer 7

A group of nodes that can all send data all at the same time, which can definitely cause collision.

Question 8

What is a hub?

Answer 8

Just a repeater. It reads a signal in and sends it out all the output ports.

Question 9

What is a switch?

Answer 9

Stores all Mac addresses of devices and stores them on a source address table. Then connects computers with ports.

Question 10

What is a full duplex switch?

Answer 10

Each port has its own collision domain.

Question 11

What is a unicast message?

Answer 11

A message just to a single machine

Question 12

What is a broadcast message?

Answer 12

A message to all machines on a network segment.

Question 13

What do routers do?

Answer 13

Connect LANs and WLANs, interpret layer 3 (network) and layer 4 (transport). Finds the best paths, reroutes traffic accordingly.

Question 14

How does routing work?

Answer 14

Layer 2 data gets removed, Ip packet is created and sent through the correct port.

Question 15

What is a route table?

Answer 15

A database of IPs and subnet masks. Also has Gateway and port currently being used.

Question 16

What are interior routers?

Answer 16

Connecting multiple LANs on the same domain.

Question 17

What are border routers?

Answer 17

Connecting domains with their ISP.

Question 18

What are exterior routers?

Answer 18

Routers the ISP owns or other backbone routers for the internet.

Question 19

What is NAT?

Answer 19

Network address translation. Basically translates between external IPs and internal IPs.

Question 20

What are the two types of NAT?

Answer 20

Static and dynamic NAT.

Question 21

What is a static NAT?

Answer 21

Always give the same mapping to the same device

Question 22

What is dynamic NAT?

Answer 22

Mapping different devices to different IPs at different times. From a “pool” of all possible IP addresses.

Question 23

What is PAT?

Answer 23

Port address translation. Dynamically routing one public IP address with multiple ports to multiple private IPs.

Question 24

What are the three types of ports and the ranges of each?

Answer 24

Well known: 0- 1023
Registered: 1024 - 49151
Dynamic and private: 49152 - 65535

Question 25

What is port forwarding?

Answer 25

Basically lets someone outside the network connect directly to a machine by specifying the public IP address and the port

Question 26

What is an ACL?

Answer 26

Access control list. Determines wether or not to drop packet.