IPv6 and Windows 10
The longer you've worked with Windows, the more likely you are to be familiar with the granddaddy of Windows networking, Internet Protocol version 4, also known as IPv4. A default network connection in Windows 10, wired or wireless, uses IPv4 but also enables the newer IP version 6. IPv6 is on by default and has been the preferred protocol in all desktop and server versions of Windows for over a decade, since the release of Windows Vista.
Without getting into the minutiae of network addressing, suffice it to say that IPv4, with its addresses based on four groups of numbers from 0 to 255, has a big problem. When the internet was young, that address space, consisting of 4.3 billion unique combinations of dotted addresses, like 192.168.1.108 or 10.0.0.242, seemed huge. Unfortunately, nobody anticipated just how big the internet would become, and the authorities who assign IP addresses on the internet have literally run out of IPv4 addresses.
The solution is IPv6, which uses 128-bit addresses and therefore has a maximum address space of 3.4 x 1038 addresses, which we are confident is enough to last for the next few generations of internet users. IPv6 is slowly but surely taking over large swaths of the internet. The giant American internet and cable provider Comcast has fully enabled its network for IPv6, with most of its competition not far behind. Major mobile carriers are also providing the majority of traffic on native IPv6 connections.
Major content providers are enabled for IPv6 as well. You can read about Microsoft's IPv6 efforts at https://bit.ly/ms-ipv6. Almost all of Google's services now work over IPv4 and IPv6, as does Yahoo. Facebook's giant data centers now run IPv6 exclusively, and Netflix has supported IPv6 for years.
Windows veterans might be tempted to shy away from IPv6, preferring the more familiar IPv4. In our experience, that's a mistake. IPv6 is here to stay. Learn about it and embrace it.
Windows provides several methods for assigning IP addresses to networked computers:
- Dynamic Host Configuration Protocol (DHCP).
This is the default configuration for Windows 10. A DHCP server maintains a pool of IP addresses for use by network devices. When you connect to a network, the DHCP server assigns an IP address from this pool and sets subnet masks and other configuration details. Many corporate networks use DHCP to avoid the hassle of managing fixed addresses for constantly changing resources; all versions of Windows Server include this capability. Most routers and residential gateways also incorporate DHCP servers that automatically configure computers connected to those devices. - Automatic Private IP Addressing (APIPA).
When no DHCP server is available, Windows automatically assigns an IP address in a specific private IP range. If all computers on a subnet are using APIPA addresses, they can communicate with one another without requiring additional configuration. APIPA was introduced with Windows 98 and works the same in all versions of Windows released since that time. - Static IP Addressing.
By entering an IP address, subnet mask, and other TCP/IP details in a dialog box, you can manually configure a Windows workstation so that its address is always the same. This method takes more time and can cause some configuration headaches, but it allows a high degree of control over network addresses. - Alternate IP Configuration.
Use this feature to specify multiple IPv4 addresses for a single network connection (although only one address can be used at a time). This feature is most useful with portable computers that regularly connect to different networks. You can configure the connection to automatically acquire an IP address from an available DHCP server, and you can then assign a static backup address for use if the first configuration isn't successful.
To see details of your current IP configuration, open Settings → Network & Internet and then, depending on your connection type, click Wi-Fi or Ethernet. Click the name of the current network, at the top of the page, and scroll down to see a compact but information-rich list of network details.
For a more comprehensive view of your network, go to Settings → Network & Internet → Status and click View Your Network Properties. That option shows a far more detailed list of network properties, covering every installed network adapter. The top of one such list on a Windows 10 PC; you can tell from this display that the IP address was automatically assigned by the DHCP server in a router at IP address 10.0.0.1.
This more expansive view of network properties includes details about DHCP servers and link speeds not found in the Properties pages for an individual adapter.
On most home and business networks, IP addresses are assigned automatically by Dynamic DHCP servers; in some cases, you might need (or prefer) to use static IP addresses, which are fixed numeric addresses.
Static IP addresses are useful if you plan to set up a web server, a mail server, a virtual private network (VPN) gateway, or any other computer that needs to be accessible from across the internet. Even inside a local network, behind a router or firewall, static IP addresses can be useful. For instance, you might want to configure the router so that packets entering your network on a specific port get forwarded to a specific computer. If you use DHCP to assign addresses within the local network, you can't be certain that the address of that computer will remain the same over time. But by assigning that computer a static IP address that's within the range of addresses assigned by the DHCP server, you can ensure the computer always has the same address and is thus always reachable.
This procedure works best if you first allow the DHCP server to assign addresses. Open the properties of the connection and make a note of the current settings.
To set a static IP address, follow these steps:
- Go to Settings → Network & Internet → Status and click Change Adapter Options.
- In the Network Connections folder, right-click the connection whose settings you want to change and choose Properties.
- In the list of installed network items, select Internet Protocol Version 4 (TCP/IPv4) or Internet Protocol Version 6 (TCP/IPv6), and then click Properties.
- In the Internet Protocol (TCP/IP) Properties dialog box, select Use The Following IP Address and fill in the blanks. You must supply an IP address, a subnet mask (for IPv6, the length of the subnet prefix, which is usually 64 bits), and a default gateway.
- Select Use The Following DNS Server Addresses, and then fill in the numeric IP addresses for one or more DNS servers as well.
When assigning static IP addresses, you must fill in all fields correctly. To avoid making a mistake that could cause you to lose your network connectivity, select Validate Settings Upon Exit. - If necessary, for an additional protocol, and click OK to save your changes.
Public and Private ip Addresses
Any computer that's directly connected to the internet needs a public IP address-one that can be reached by other computers on the internet-so that information you request (webpages and email, for instance) can be routed back to your computer properly. When you connect to an internet service provider, you're assigned a public IP address from a block of addresses registered to that ISP. If you use a dial-up connection, your ISP probably assigns a different IP address to your computer (drawn from its pool of available addresses) each time you connect. If you have a persistent connection to your ISP via a DSL or cable modem, your IP address might be permanent-or semipermanent if you turn off your computer when you leave your home or office to travel and your assigned IP address is changed when you reconnect on your return.
On a home or small office network, you don't need to have a public IP address for each computer on the network. In fact, configuring a network with multiple public addresses can increase security risks and often requires an extra fee from your ISP. A safer, less costly solution is to assign a single public IP address to a router or residential gateway (or a computer that performs that function). All other computers on the network connect to the internet through that single address. Each of the computers on the local network has a private IP address that's not directly reachable from the outside world. To communicate with the internet, the router on the edge of the network uses a technology called Network Address Translation (NAT) to pass packets back and forth between the single public IP address and the multiple private IP addresses on the network.
The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IPv4 address space for use on private networks that are not directly connected to the internet:
- 10.0.0.0-10.255.255.255
- 172.16.0.0-172.31.255.255
- 192.168.0.0-192.168.255.255
In addition, the Automatic Private IP Addressing feature in all post-1998 Windows versions uses private IP addresses in the range 169.254.0.0 through 169.254.255.255. Routers and residential gateways that use NAT almost always assign addresses from these private ranges. Linksys routers, for instance, typically assign addresses starting with 192.168.1.x. If you're setting up a small business or a home network that will not be connected to the internet, or that will be connected through a single proxy server, you can freely use these addresses without concern for conflicts. Just make sure that all the addresses on the network are in the same subnet.
Mobile hotspots
Some devices with data connections on a cellular network allow you to turn the device into a mobile Wi-Fi hotspot-a feature sometimes referred to as tethering. This capability is invaluable when you need to get some work done on a portable PC, and an affordable, reliable Wi-Fi connection isn't available. Most modern smartphones, including iPhones and Android devices, can act as a hotspot, although the cellular data provider must allow this capability.
The downside of using a mobile hotspot where you pay by the megabyte or gigabyte is potentially higher costs (especially if you're roaming outside your home network) or the risk that you'll hit your data limit and have your connection throttled or stopped completely. To avoid that possibility, Windows 10 identifies mobile hotspots as metered connections and automatically limits certain types of background activity. By default, the list of restricted activities includes downloads from Windows Update and always-on connections to an Exchange Server connection in Microsoft Outlook.
If Windows 10 doesn't realize that a specific network is on a pay-as-you-go connection, open Settings → Network & Internet → Wi-Fi, and click or tap Manage Known Networks. In the list of networks that appears, tap the one you want to mark as metered, and then tap Properties. Slide the Set As Metered Connection switch to the On position.
For even more aggressive management of a potentially expensive wireless network, click Set A Data Limit To Help Control Data Usage On This Network. That opens a dialog box where you can set a data limit on a per-connection basis; the limit can apply monthly or on a one-time basis, and you can set the limit to a specific value, expressed in MB or GB.
To see how much data you've used on each connection over the past 30 days, open Settings → Network & Internet → Data Usage. That page shows total data usage over the past 30 days. Click any connection to see that usage broken down on a per-app basis.
Finally, we would be remiss not to note that recent versions of Windows 10 have expanded the Mobile Hotspot feature to support sharing of any network connection on a Windows 10 PC. If you've paid for Wi-Fi on an airplane, for example, you can share that connection securely with up to eight other devices.
You'll find all the options you need by going to Settings → Network & Internet → Mobile Hotspot. There are four settings to pay attention to here.
- To begin sharing your network connection, flip the Mobile Hotspot switch to the On position.
- Choose which connection you want to share. In the screenshot shown here, Ethernet is the only option, but you might find yourself in a location where you have multiple connections: wired, Wi-Fi, or even mobile data.
- Choose how to share your connection: over Wi-Fi or Bluetooth.
- Click Edit to change the connection name, replace the default random password with one of your own choosing, and customize the type of connection.
With that setup complete, you can turn on your mobile hotspot from the network flyout or from Settings and connect any Wi-Fi- or Bluetooth-capable device (including a mobile phone) to your Windows 10 network connection.
