Windows 8 : Configuring networking (part 4) - Managing network settings - Configuring IP settings

Configuring IP settings

As an administrator of desktop computers in an environment with multiple computers, you probably won’t have to configure a production desktop computer’s IP settings manually very often. Most organizations use a Dynamic Host Configuration Protocol (DHCP) server. A DHCP server automatically configures all the network settings that are necessary for a computer to operate on the network and connect to the Internet.

However, in some cases, you might need to configure a computer’s IP settings manually to troubleshoot network problems.

USE DHCP WHENEVER POSSIBLE

Unfortunately, many organizations do not use DHCP servers and instead rely on their desktop and network administrators to track, assign, and configure IP addresses manually on all the machines in the organization. This occurs even in organizations that have hundreds of devices.

In many cases, these networks have eschewed some modern tools because of inexperience with or fear of DHCP or an automated technology. The alternative, however, is massively inefficient and extremely error prone.

Even as a desktop administrator, you can recommend improvements and automation in your environment. With so many IT departments being asked to do more with less, it’s up to every IT staff member to find ways to streamline common tasks. If you work in an organization that doesn’t use DHCP, research the pros and cons of the technology in the desktop environment and don’t be afraid to take a recommendation up the chain of command.

DHCP isn’t the only automated method by which a computer can obtain an IP address. When no DHCP server is available, but a Windows 8–based computer is configured to obtain an address by using DHCP, that computer will fail over to a mechanism known as Automatic Private IP Addressing (APIPA).

When a DHCP server is unavailable, APIPA automatically assigns an IP address in the range of 169.254.0.1 to 169.254.255.254 to Windows 8 clients. The default network subnet mask of 255.255.255.0 is used for all APIPA addresses, and all the Windows computers using APIPA reside on the same subnet and are visible to one another on the network. In Windows 8, all network adapters have APIPA enabled, although this feature can be disabled on a per-network adapter basis. In general, APIPA is rarely disabled because most organizations rarely have major DHCP problems.

TROUBLESHOOTING: SUPER-FAST IP TROUBLESHOOTING

If you must troubleshoot a Windows 8–based computer for which a user has reported a problem connecting to network resources, check whether that computer has a 169.x.x.x address. If it does, you know that the computer is not receiving a DHCP-assigned IP address. This will help you identify the cause of the problem quickly, which could be that the DHCP server is down or that a network cable somewhere is unplugged.

Now that you understand that Windows 8–based computers can automatically receive IP addresses by two methods, you need to understand how you can modify a computer’s IP configuration manually if that becomes necessary. To configure a computer’s IP settings manually, complete the following steps:

1. Open Network And Sharing Center.

2. Tap or click Change Adapter Settings.

3. When the list of network adapters appears, press and hold or right-click the appropriate adapter and, from the shortcut menu, choose Properties (Figure 9).

   

   Figure 9. Opening the Properties page for the Ethernet adapter

4. Under This Connection Uses The Following Items, choose Internet Protocol Version 4 (TCP/IPv4).

5. Click the Properties button to open a dialog box like the one shown in Figure 10.

   This system is currently configured to obtain an IP address from a DHCP server.

6. Provide appropriate configuration settings and tap or click OK.

Figure 10. The default Windows 8 IP settings

DON’T USE A RANDOM IP ADDRESS

As you’re manually assigning IP addresses to your desktop computers, make sure that you verify the IP addresses you intend to use. Most organizations that have a lot of IP addresses have a person who is responsible for ensuring that only valid IP addresses are deployed and that IP addresses are not accidentally reused.

As you can see in Figure 10, a number of items can be configured for each network adapter. In this example, the network adapter is configured to Obtain An IP Address Automatically and to Obtain DNS Server Address Automatically. In short, the adapter is using DHCP. To configure the adapter to use manually assigned IP settings, choose Use The Following IP Address and Use The Following DNS Server Addresses.

After you do so, provide these values:

• IP Address This is the IP address you want to assign to this Windows 8–based computer.

• Subnet Mask The subnet mask helps Windows determine which resources are local to the computer and which are remote. When you attempt to access a resource that is identified as remote from the Windows 8–based computer, Windows automatically passes the traffic to the default gateway.

• Default Gateway The default gateway is the doorway into and out of the local network. When Windows 8 attempts to access resources that are identified as local, the network traffic can safely ignore the default gateway. However, when Windows attempts to access remote resources, that network traffic passes through the default gateway and is routed around the network and possibly even the Internet until the desired remote resource is located.

• Preferred DNS Server When you browse to www.microsoft.com, your computer doesn’t have any idea what www.microsoft.com means. Behind the scenes, Windows is looking up www.microsoft.com on a Domain Name Server (DNS) system. DNS is a phonebook for the network. Without DNS, you would have to remember the IP address for every resource you want to use.

• Alternate DNS Server Because DNS is so important to the proper functioning of a network, most organizations have more than one DNS server. The alternate DNS server is used when Windows is unable to use the preferred DNS server.

The IP addresses with which you’re working in this section are also referred to as IPv4 addresses; when someone talks about setting an IP address, she is generally referring to an IPv4 address. These addresses are expressed in dotted quad notation; they look like this: 192.168.0.1. There are four numbers (quad), and they’re separated by periods (dotted). Subnet masks provide a way for a huge network to be broken down into smaller, more manageable pieces. These smaller pieces are called subnets, which is where the term “subnet mask” originates. The default gateway is the IP address for a local router, which is a hardware device that connects separate subnets and networks and enables them to communicate with one another. The settings for a manually configured network adapter on Windows 8 might look similar to the settings shown in Figure 11.

Figure 11. A system with manually configured IP settings

Note

MORE INFO LEARN MORE ABOUT IPV6

Although IPv4 still dominates the desktop, IPv6 is becoming more widely available. Eventually, you will have to learn about IPv6 and how it works. To that end, Understanding IPv6, Third Edition by Joseph Davies (Microsoft Press, 2012) goes into great detail about this networking protocol, and it includes information on Windows 8 and Windows Server 2012.

A number of IP addresses are reserved for special use. In addition, the Internet Engineering Task Force (IETF) has set aside four IP address ranges. Addresses in these ranges cannot be used on the Internet but can be used on internal networks. When they are used on internal networks, specialized network devices at the network edge translate these private IP addresses into ones that are usable on the Internet.

Here are the four reserved private IP address ranges:

• 10.0.0.0 through 10.255.255.255

• 169.254.0.0 through 169.254.255.255 (APIPA, as previously discussed)

• 172.16.0.0 through 172.31.255.255

• 192.168.0.0 through 192.168.255.255

Whereas normal IP addresses are unique around the world, the addresses in the private IP address ranges can be used in any organization because those addresses can’t be used on the Internet. Because of this, and because the world is running out of IP addresses, many organizations use these private IP address ranges, so make sure you understand them.

Note

PLANNING IP ADDRESS THAT YOU CANNOT USE ON A WINDOWS 8–BASED COMPUTER

In addition to these private IP address ranges, here are some special IP addresses that you can’t use on a computer running Windows 8:

• 127.0.0.1 This is known as the loopback address. It’s used for testing network connectivity.
  

• 224.0.0.0 to 239.255.255.255 This address range is known as the multicast range and can’t be used on individual computers.

• 240.0.0.0 to 255.255.255.254 These addresses were reserved when IPv4 was conceived.

• 0.0.0.0 This IP address represents the network and can’t be assigned to an individual computer.

• 255.255.255.255 This is a catch-all broadcast address that represents every computer on the network.

• Network address As organizations break up their networks, multiple network addresses are created. These cannot be used on individual computers. Check with your network administrator to learn about your company’s network addresses.

• Broadcast address Every subnet has its own broadcast address that can’t be used on computers.