What’s a Network Service?

Network services are critical to what we do nowadays on computers. Without them, most of the functionality that we use on computers wouldn't really work.

Now, we've created an app for our business. This app allows an end user to see a list of all the songs that we have on our server and also be able to stream that music. So we need to set up a service now on our server in order to help facilitate that. That's going to be our network service.

What a service is

First, let's take a look at just what a service is, specifically in the scope of what it looks like on Windows, on your Windows machine. Well, any machine really: when you start it up, there's a lot of different programs that get launched. These are all of our programs that come up, giving instructions to the computer on how it's going to operate.

The thing is, when you launch the computer, there are many programs that get launched. And then when you log into the computer, there are more programs that get launched. And then when you actually launch a program, then there are more programs that get launched. So they get launched at different times, and they also get launched under different user settings. For instance, if you launch a program, it gets launched as you as the user, whatever you're logged in as. If there are programs that get started up when you log into the computer, often those are associated with your user account as well.

However, this is problematic, because there are some things that we want to launch and have up and running that, number one, aren't tied to our user. It's tied to a different user on the machine, or the system on the machine. And number two, we want some of these programs to be up and running before we ever log into the machine. So we want services that run while we're not logged in. That's what services allow us to do: services allow us to create, from these programs, a service on the machine that is up and running all the time.

The services console

So let's see what this looks like on an actual machine. What I'm going to do is open up the Windows menu right here and type in services and hit enter. That's going to pop up my services console here. And what I see here is a list of a bunch of different programs that have been set up as a service. These are programs that you don't have to launch; they will get launched automatically. Maybe it's because of some sort of trigger. Maybe they're automatically launched when you turn on the machine. There's this startup type right here. So many of these could be manual and have to be triggered by something. Or some of these are automatic and get started when the machine launches, while others are set up automatically but have a delay, so they're not started right away.

So these are the programs right here. It gives a description. We see that many of these are running already, and I've not launched them, but they are running. And we see what account actually has launched this. So many of these are local services. Some of them are local systems. Many of these we can even see in here network services, so these are probably some sort of service that's providing some sort of service on the network. So we see now all of these different programs that are launched on this machine.

Now, Linux and Unix systems do have something similar. They just call it something different. They call it a daemon. Those are the programs that are launched as services on a Linux or Unix machine.

What makes it a network service

So then the question is, what is a network service? It's the same thing. It's just one of those services that's running on the machine, but it's providing services to the network. What it allows this machine to do is that if there are requests that are being made of it, it can respond to them without having somebody having to log onto this machine and start up that service.

DHCP

Let's first of all take a look at DHCP. I'm going to do a brief explanation of what DHCP is so we have some understanding about it. What it is is that your machine, when it connects into the network, needs an IP address for it to have really any kind of functionality. So when it first connects into a network, typically what it does is it requests and says, "Hey, can I get an IP address?" And it gets a response and says, "Okay, here's an IP address." And it's the DHCP services that allow that to happen.

So let's take a look at what DHCP looks like. I'm back on my Windows machine and I have the services console already open, and I'm going to scroll down to where I can find the DHCP client. So this is the client side. This is on this machine, when the machine starts up. This is the program that makes the first request and says, "Hey, can I get an IP address?" and then gets a response from another machine that is going to be a DHCP server and says, "Okay, here's an IP address." So if I were to go on a Windows machine that's actually supplying the IP addresses, I would see a DHCP server on the other side of this. So the DHCP server is the network service. That's what's set up to provide IP addresses for these clients. So the network service is that service that's providing some sort of services to the end client. In this case, it's the service that's providing IP addresses for the end client.

Browsing the web

But let's take a look at another example. Let's take a look at web, when you're browsing the web, because it looks quite a bit different when you're on the internet. When you use some sort of browser, perhaps it's Chrome or Firefox or Safari or whatever you're using to browse the internet, what does that look like?

What I could do is I could scroll through this services console to try to look for Chrome, but I'm not going to find it within the services tabs here. Instead, I'm going to open up Chrome, and it's going to launch an app. And what I'm going to do is plug in what am I going to connect to. So maybe we want to connect to techknowsurge.com, and I hit enter right there.

So what's happening right here? This is the client right here. This is an app that I've launched, and then I've made a connection to my website right here. And now the question is, what is on the other side of that? On the other side of that is some sort of service that's running on that other machine providing those network services.

A couple of examples of what it could be on the other side: it could be something like Apache. I might have installed Apache as a service on the other side, and that's up and running providing that network service, those web pages, and delivering those web pages. Or maybe it's IIS. IIS is a Windows version, or a Microsoft version, of delivering websites to end users. So in this example right here, we have that app that we launch on the computer, and then it's contacting some sort of service that's running either Apache, or maybe it's running IIS, or there are a lot of other different types of services out there that could be delivering these web pages and these websites.