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Hi there, Jess Stratton here, and welcome to Monday Productivity Pointers. This week on Monday Productivity, I thought I'd go back to basics a little bit. Because, knowing how the Internet works goes a long way in learning how to do your own troubleshooting. So this week I am going to talk about Firewalls, now if you have Internet access at home you most likely had to purchase a Firewall router or maybe you tried to do something on your browser or work and you got blocks because of their Firewall. In this video I am going to talk about what a Firewall is.
What it does. What is blocking? And I'm going to talk a little bit about how data travels through the Internet using ports. It monitors how traffic, that is data, goes over the Internet to finally get to you. So we have a lot to cover, so I"m going to get started. I've got some common ports open here on my screen. And I'm going to get to those in a second. But first thing we need to cover, to understand what this means, is how data travels through the Internet. Different types of data that open with different types of apps.
Such as a web browser versus an email program. Travel through different ports. So what's a port? Well I like to use radio stations traveling through airwaves as a perfect way to explain it. Radio waves travel through the air and your radio is a receiver. It picks up the airwaves on the other end. Now, each dial on your radio is set to a different frequency of what radio wave is traveling. So to get to the country music station, you might set your dial to 99.5. To get rock, move the dial to a station that's listening on a different frequency.
Say 103.7, if we can move this analogy to the computer. Instead of a frequency on an airway, different kinds of internet data travels through different port number. Your computer has a built in firewall, in addition to the firewall on your router. So think of the firewall as the radio portion of the analogy. The firewall is always listening for data traveling on various ports and from there it knows what app to send the right data to.
Sometimes internet data travels through a certain port number that your firewall won't allow. In that case the firewall won't send the data through, it just won't allow it to pass. So, here's some common internet ports. And remember, ports are how data travels through the internet. So, you may have seen port 110, or POP3 e-mail or port 25 which is how SMTP e-mail travels. There's also port 143 which is how IMAP, which is the third way of sending e-mail, travels through the internet.
Now, when you open a web browser and you're browsing websites, you're using a protocol named HTTP and that actually travels over port 80. And when you do secure browsing such as a shopping checkout screen, you may notice that your browser changes to the HTTPS protocol at the top of the screen. A padlock also appears at that time. That time your browsers switches to port number 443. You've also probably seen these ports in action without realizing it.
When you setup an email account, you specify the incoming server. Say mail.verizon.net. I'm going to open up this browser, where I took a procedure online. Or how to connect to the internet, you may have seen these instructions. For example, when you're hooking up a new email system, and they have their own instructions as to how to configure your email client. So these are ports in action, when you setup the email account, you have to specify the incoming server, say mail.verizon.net. And you have to specify that it's going to come in on port 25.
That's why port 25 is this well known standard port that's used to send email. For the last thing I want to cover when I talk about firewalls is what happens when something is blocked that you need to get through. Well, usually, firewalls are doing their job, and protect you from malicious software traveling through various ports on the internet. And you may have ports open on your computer, in which case that data can just get right through. So if you're at an office, and your administrator has blocked it, there's nothing you can do about it short of going in and talking to your administrator about it.
But when you're home, you have some more choices. I'm going to open up this window here. This is what a typical home network diagram looks like. This cloud over here is the internet. This is the unknown internet. Over here, this little brick wall, this is what your external IP address is. Now every network has an IP address. What you may not realize is you actually have two. You have an internal one that's only known to your local area network, and an external one, the IP address that's visible to the rest of the world.
Now the job of your firewall modem down here is to provide the rest of the world with that external address. But hide your internal address. So I can see here that there's one external address that's pointing to the internet. Now, my firewall modem has two. It has an external IP address of 220.127.116.11. But it also has this special internal IP address, which is 192.168.1.1. That may sound familiar to you.
It's also frequently something like 10.0.0.1. So the job of this modem is to be a firewall, and to block any traffic that's coming through to this external address. Evaluate the port number, and see where it's going. As you can see, on my internal network. I have things like an XBox console, and an iPhone. And maybe some family desktop computers and some laptops, and also a printer. All those things have to get their own IP addresses. Now, it's outside the scope of this lesson how to see what they are, but it's very easy to find out what the actual internal and external IP address of your devices.
So, what happens when traffic is blocked from this firewall and we really want it to get through? Well in this case, you need to look up in the manual of your firewall to know how to log into it. Because you can actually control those settings. So the last thing I want to show you is this tab I have over here. This is what happens when you login to your firewall router. You get a web interface in which you can do things like change the wireless name and the wireless password for everybody to use. But way over here on the left hand side of the screen, I'm more interested in something called Port Forwarding.
So when I come into this screen, I can see a service name that I want to add. Plus the starting point and the end point, and finally the computer name that it's going to. Now that's the internal IP address name. So don't worry if you don't understand this too much. The point is just to understand how data travels over the internet. And how you do have quite a bit of control to block it and allow and fine tune where you want that traffic to go.
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