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'''Note:''' The Internet is a packet-switching network. This means that your email, for example, is broken down into small individual packets which are then sent independently of each other along the many possible routes on the network that connect you to your friend's computer. These packets are then reassembled at the receiver's end to re-create your email. Important! You do not control how data travels through the Internet once you hit the send button.

Now that you're connected, let's discuss what happens when you request to open a particular website and how this site then delivers back to your computer. Numerous protocols and technical standards govern how the Internet and all of its users locate and communicate with each other. The most important of which we will discuss has to do with Internet addressing. Because everyone on the Internet adheres to these, you are able to open webiste.com and send an email from your computer to a friend's mobile phone in another country.

Internet routing is possible because every computer is uniquely identified on the network by what is known as an IP address. These addresses look like 83.169.39.231 and are the building blocks of Internet addressing. Whenever you want to open a website from your computer, the Internet needs to know your IP address and the IP address of the server the website is hosted on, to make the connection. Important! Your IP address is assigned to you by your local ISP or if you are using mobile Internet, by your telecommunications provider. In most countries ISPs are obligated by law to collect and store traffic data (which IP requested a connection to which IP and when) . This is used primarily for identifying user activity on the Internet at a later date and is the main tool in the hands of Internet police.

2. Next, go to http://whois.net/ to find out who that particular IP address is registered to.

Even though all computers connected to the Internet are assigned an IP address, we usually do not know these addresses nor do we use them when opening a website. Numbers are quite difficult to remember (how many phone numbers do you know by heart?) and for this reason we assign names as addresses for our websites (also known as a Universal Resource Locator – URL). These names and their associated IP addresses are recorded in the Domain Name System (DNS). This is akin to the Internet's telephone directory and is another critical component of Internet routing and operations. DNS is hierarchical, meaning that your computer can have its list of URLs and corresponding IPs, your ISP will have a list, the national provider will have a list and so on, right up to the root DNS servers (of which there are 13). Should your computer not have an entry for www.livejournal.com it will ask the next list up in line – the ISP's and so on. Whether browsing websites or sending email, DNS always plays a part. Below is a diagram describing how DNS is utilised when you search for the LiveJournal website.

3. Manually set the DNS servers to OpenDNS addresses (208.67.222.222208.67.220.220) or use two of the root DNS servers (http://en.wikipedia.org/wiki/Root_name_server ).

The last part of the Internet's infrastructure concerns the applications we use to send and receive content on the Internet. These include your browser, email program, chat client and every other software on your computer that utilises or help you interact on the Internet. Every application has its particular language and protocols and these often affect how information is transmitted between two computers on the Internet. This usually involves a type of technical language (protocol) by which it communicates or the channel (port) it selects for communication. For example, some applications send data in a clear-text format and every computer/router that stands in-between the communicating parties can access and understand the transmitted information. Other applications take special care to ensure privacy for the communicating parties. For example, when you connect to http://google.com your browser is using the 'http' protocol on port 80. However when the website's address is preceded by the letters 'https' (https://mail.google.com) your browser begins to use the Secure Sockets Layer (SSL) protocol on port 443. The majority of this course is explaining and exploring the different ways that applications interact on the Internet, directly impacting upon your privacy, anonymity and authentication of the transmitted message.