In this workshop we’ll present an overview, in the context of Linux, of the layers that make up the “five layer” TCP/IP model of networking. We’ll start by introducing Ethernet, comparing it with other alternatives and describing the CSMA/CD principle upon which it works. We’ll talk about hardware (MAC) addresses, and how they’re used along with the ARP protocol and gateways to route messages. Then we’ll move to the Internet Protocol (IP), talk about how the Domain Name System (DNS) works, and how DNS lookups are configured on a Linux computer. Next we’ll move up to the Transport layer and talk about the TCP and UDP protocols, and introduce the concept of ports. We’ll take a look at how ethernet interfaces are represented and configured under Linux. Finally, we’ll talk about a few network monitoring tools.