A firewall is one of the most powerful ways our devices can defend themselves by filtering incoming and outgoing traffic based on a set of user defined rules. But what does this mean in practice? Well, on her holiday, Nicola needs to make some decisions about the kinds of activities she wants to do.

She downloads a brochure and starts to look at all the options. A few catch her eye, but she has a few criteria to keep in mind; her budget, her time, and safety. Bungee jumping looks like a lot of fun but maybe it's a little pricey and would take them all a day to get to and from. So she decides against it. Laying on the beach is free but not that interesting. She decides to spend no more than a few days doing it. Scuba diving looks great but only a few people in the group have scuba licenses. So she decides to go with a cheaper option and spend a day snorkeling on the reef.

A day trip to the capital city sounds fun but one of her family members visited a few years ago and had told her that it didn't seem that safe. Last up she looks at cultural trips they could do and decides that a trip up the mountain would make for some great photos. Now, a firewall does the same thing for our devices. It uses a set of criteria as filters and decides, based on this, what kind of traffic to let into and out of our devices.

Lectures

What is The Cloud? - DHCP and DNS - Encryption - Hubs, Switches and Routers - The 7 Layers of the OSI Model and Encapsulation - Unicast, Multicast and Broadcast

Firewall