Information I Think is Worth Knowing

Question 1

What is nmap?

Answer 1

It’s a really popular command line tool that maps networks; you can do ping sweeps and see what is up and available; see operating systems; see the ports that are available and what is open

Question 2

TCP

Answer 2

Operates on level 4; conducts a three way handshake between a client and a server, and then establishes a connection; connection oriented; very reliable

Question 3

UDP

Answer 3

Detects if packets are corrupted when they are received by a client using a checksum, but it’s connectionless; it’s unreliable; great for streaming audio and streaming video; not accurate

Question 4

ICMP

Answer 4

Internet Control Message Protocol; used to communicate information about network connectivity issues back to sender (like pings)

Question 5

Generic Routing Encapsulation (GRE)

Answer 5

Used as a simple and effective way to create a tunnel, called a GRE tunnel, over a public network; wraps up the data and sends it over a public network; does NOT provide any encryption

Question 6

Internet Protocol Security (IPSec)

Answer 6

Used to protect one or more data flows between peers; think of it as the secure version of GRE; lets you encrypt your tunnel to protect your data from prying eyes. Has two elements Authentication Header (a protocol within IPSec that provides integrity and authentication) Encapsulating Security Payload (ESP)(Provides encryption and integrity for the data packets send over IPSec)