Your Windows operating system can’t do very much without an IP address. In this video, you’ll learn how Windows assigns IP addresses to network interface adapters.
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Without an IP address, your computer can’t communicate to anything on your local network, and it certainly can’t communicate to anything on the internet. But we often don’t even think about the process that occurs to get this IP address configured on our computer. That’s because, most of the time, this is all done automatically through DHCP, the Dynamic Host Configuration Protocol.
This is a protocol that automatically assigns an IP address to your computer. So you can plug-in your computer at home. You can connect to a wireless network at a coffee shop. And your computer automatically gets the IP address it needs and is able to communicate properly across the network.
Well, if you connect to a network, and you’re not able to receive an address from a DHCP server, maybe the DHCP server is not providing any addresses, or maybe the DHCP server’s not on your network anywhere. If that’s the case, you will be assigned an IP address internally by your computer. This is called an APIPA address, or Automatic Private IP Addressing.
This is also called a link-local address. That’s because this IP address allows you to communicate with everyone on your local network, but it does not allow you to communicate outside of your network. So if you’ve been assigned an APIPA address, you would not be able to communicate out to the internet.
This is something that is assigned statically by your computer. It’s not something that you’re inputting yourself. It’s not being assigned by DHCP server. It is completely automatic by your operating system.
If you look at your IP address, and you’ve been assigned an IP address between 169.254.1.0 through the address 169.254.254.255, then that is an APIPA address. That is the only time that you would receive anything that’s in this IP address range. And you’ll also notice that you have no internet connectivity as well, because this is a link-local address.
Another option that you have for IP addressing is a static address. With a static address, you’re not relying on a DHCP server to provide an automatic address. You’re not having your operating system assign an APIPA address. Instead, you are assigning everything manually. You are statically putting in the IP address of your computer, the subnet mask, and any other details you need to be able to communicate on this network.
Your network administrator will be the one to provide you with all of the details of what you need to assign manually when you statically assign an IP address. But generally, we don’t even do any static IP addressing. Everything is done through DHCP so that everything is automated when you connect to the network.
One of the reasons we like to perform this process automatically is there are a lot of details in the IP addressing. For example, you need first an IP address. This is a very unique address that’s assigned to your device. This also includes a subnet mask. This is going to help you identify what subnet your computer belongs to.
And you would also be assigned a gateway IP address that allows your computer to communicate outside of your local subnet. This is the configuration setting that allows you to type in the name of a server in your browser. And behind the scenes, the domain name services will convert that name to an IP address so that you can then communicate directly to that computer across the network.
You can see now why DHCP would be the recommended setting instead of manually configuring all of these different IP addresses and hoping that you don’t misconfigure any of them. You can simply have the DHCP server assign everything.
You can even configure your DHCP server not to assign IP addresses based on a large pool, but to assign a specific IP address to a specific device. This reserved address setting is usually configured in your DHCP server. And it usually associates the MAC address with an IP address so that your web server or your file server will always get the same IP address from the DHCP server.
One useful IP address to memorize is the IP version 4 loopback address that’s inside every single computer. If you go to your computer and you were to ping 127.0.0.1, you’ll see that your computer should respond. If it doesn’t respond to a loopback address, then there’s a serious problem with the IP configuration settings inside of your computer.
One way to look at the network settings in Windows is to go to your Control Panel and choose Network and Sharing Center. If you can find your Network icon in the bottom toolbar, you can right mouse click and choose Open Network and Sharing Center from there as well.
From the Network and Sharing Center, you can choose to Change Adapter settings, and it will list all the different adapters that are on your computer. On my computer, I only have a single adapter called Ethernet0. And if I click Ethernet0, I can disable this device, diagnose this connection, rename the connection, view the status, and change the settings of this connection.
If we choose View the Status, then I can see all of the current status settings for this adapter. You can see it does have IPv4 connectivity to the internet. And the media state is enabled. And if I click Details, you’ll be able to see all of those IP addresses we were talking about.
DHCP is enabled. It was assigned a DHCP address. This is an IPv4 address of 10.1.10.25. I can see that my subnet mask is 255.255.255.0. My default gateway is 10.1.10.1. And my DNS servers are 8.8.8.8 and 8.8.8.4. That’s a lot of IP addresses. And you can see now why DHCP is so useful. It’s able to configure all of these instantly when I start my computer.
You can also view all this information at the command line. And it’s Windows 8, so I’ll hit my Windows button and type in cmd and hit Enter. From the command line view, we can type ipconfig and get details about each one of the adapters in my computer. Here’s my ethernet adapter, Ethernet0. And you can see IP address, subnet mask, and default gateway information.
If you also wanted to see more details about this adapter. We can use that same IP config command with a /all. This will list out many more details about this adapter. We can now see MAC addresses. We can see details about which DHCP server assigned this address. And we can see DNS server information in here as well.
If you’d like to make any changes to the IP configuration settings inside of this computer, we go back to our Control Panel. We can choose this particular adapter and choose Change Settings of this Connection. It will list out all of the different network drivers that are configured for this adapter.
I’m going to scroll down to the bottom to the internet protocol version 4 TCP/IP V4 configuration. If I click Properties or double-click, you can see that this is configured to obtain an IP address automatically or obtain a DNS server address automatically.
Maybe we would like to configure an IP address manually. So instead of choosing Obtain an IP Address Automatically, I’ll click we Use the Following IP Address button, and I’ll add my own IP addresses into this configuration. So I might want to add the IP address, subnet mask, and default gateway. And then, you have the option to also add DNS server information manually as well.