Networking & the Internet Study Guide

What is a network?

A series of interconnected devices that can communicate with one another.

Who is the client in the client-server model?

The client is you.

What does the server do in the client-server model?

The server accepts requests and gives the info back.

What is an IPv4?

A unique identifier for a network made up of four numbers separated by periods.

What is a MAC address?

A unique identifier for a physical device.

What protocol establishes a connection between two devices?

TCP/IP.

What is a packet?

A chunk of information sent from one computer to another.

What are the three messages in the TCP three-way handshake?

synchronize, synchronize-acknowledge, and acknowledge

Why are there three messages in the handshake?

To ensure that both computers can hear each other.

What does the OSI model provide?

A universal framework of 7 layers for how information should be broken up to be sent over the Internet.

What are the top three layers of the OSI model?

Application, Session, & Presentation Layers.

What does the Transport Layer ensure?

That packets are recombined in the right order.

What occurs at the Network Layer?

Routing across the Internet, connecting one IP address to another.

What does the Data Link Layer do?

Establishes which machine in a network gets the data through the MAC address.

What is the Physical Layer responsible for?

The communication medium and what signals are transmitted.

What protocol governs web pages and web data?

HTTP.

What is the difference between GET and POST requests?

GET transfers data in the URL, POST transfers it in the packet.

What is Transport Layer Security (TLS)?

A cryptographic protocol that encrypts information sent over the Internet.

What is HTTPS?

HTTP wrapped in TLS.

What does a web server send to verify its identity?

An SSL certificate.

What does the Domain Name System (DNS) do?

Translates a URL into an IP address.

How are IPv4 and IPv6 addresses related?

They both point to the same resources.

How are IPv4 and IPv6 addresses different?

IPv6 is written differently to prevent running out of addresses like IPv4.

What is network enumeration?

The process of mapping out a network and all the services running on it.

What does a firewall do?

Uses rules to filter out traffic based on its source, port, and protocol type.

How can a firewall be evaded?

By changing the transmission unit size to make packets small enough to get through.

What is spoofing?

Disguising an unknown IP address as a known and trusted address.

What was a limitation of the IP spoofing attempt?

We couldn’t get any traffic back.

What is a consequence of IP spoofing?

Inability to receive returned traffic.

What is the significance of packet size in network transmission?

It affects the ability to bypass firewalls and network rules.