The Internet

What is Packet Switching?

Splitting messages into packets that can travel independently of one another.

What is the end to end principle?

That the two endpoint hosts should be in control of the communication.

Why are two advantages of the end to end principal?

• Can survive a partial network failure as data can be resent

• Packets can quickly route around network failures

What are the three parts of a domain name?

• Protocol

• Fully Qualified Domain Name

• Path

How are domain names converted into Ip addresses?

The Domain Name is sent to a Domain Name Server which searches for the corresponding IP address. If it does not have it saved, it asks other Domain Name Servers

What are three ways that a firewall protects a server?

• Static Packet Filtering

• Stateful Inspection

What is static packet filtering?

When packets are filtered by source, port number and packet header

What is Stateful inspection?

A dynamic version of static packet filtering where context of communications is also considered

What is a proxy server?

A server that acts as a gateway between a device and the internet

How does symmetric encryption work?

The sender and receive use the same key to encrypt or decrypt the message.

How does asymmetric encryption work?

The sender and receiver use different keys to decrypt / encrypt. The sender uses a public key of the receiver and then the receiver decrypts the message using a private key

What is a digital signature?

A signature is added to the end which is also encrypted. If when received it is still correct, the data is authentic

What is a digital certificate?

A certificate given by certification authorities that contain information about the owner of the private key.

When are digital certificates generally used?

In banks and e-commerce websites