Configuring and Troubleshooting Network Connections

Configuring and Troubleshooting Network Connections
Presentation: 65 minutes Lab: 60 minutes After completing this module, students will be able to: Describe how to configure a local area network (LAN) connection with IPv4. Describe how to configure a LAN connection with IPv6. Explain the implementation of automatic IP address allocation. Explain the methods for resolving computer names. Explain the troubleshooting process for network connectivity problems. Required materials To teach this module, you need the Microsoft® Office PowerPoint® file 20687B_04.pptx. Important: We recommend that you use PowerPoint 2007 or a newer version to display the slides for this course. If you use PowerPoint Viewer or an earlier version, all the features of the slides might not display correctly. Preparation tasks To prepare for this module: Read all of the materials for this module. Practice performing the demonstrations and the lab exercises. Work through the Module Review and Takeaways section, and determine how you will use this section to reinforce student learning and promote knowledge transfer to on-the-job performance. Module 4 Configuring and Troubleshooting Network Connections

Troubleshooting Network Connectivity
Module Overview 4: Configuring and Troubleshooting Network Connections Troubleshooting Network Connectivity This module’s primary goal is to teach students how to configure network connections.

Lesson 1: Configuring IPv4 Network Connectivity
20687B Lesson 1: Configuring IPv4 Network Connectivity 4: Configuring and Troubleshooting Network Connections Demonstration: Configuring an IPv4 Address Some students already may have an understanding of these concepts. If this is the case, you can use this lesson to set the scene for the rest of the module. Present the topics in such a way that they are a refresher for the more-knowledgeable students.

An IPv4 address identifies a computer to other computers on a network
20687B What Is an IPv4 Address? 4: Configuring and Troubleshooting Network Connections An IPv4 address identifies a computer to other computers on a network IP Address IP Address IP Address Subnet 2 IP Address IP Address IP Address Subnet 1 Use the slide as an example that you can discuss with your students. Emphasize that all computers in the slide have the same first 3 octets in their IP addresses. Talk about the dotted decimal notation for IPv4 binary numbers, and then reference the second subnet, showing the difference in IP address. The IP address identifies a computer’s location on the network in the same way that a street address identifies a house on a city block. And just as a street address must identify a residence uniquely, an IP address must be globally unique to the network, but follow a uniform naming format. Each IP address includes a network ID and a host ID. The network ID (also known as a network address) identifies the systems that are on the same physical subnet bounded by IP routers. All nodes on the same network must have the same network ID, which must be unique to the network. The host ID, which also is known as a host address, identifies a workstation, server, router, or other TCP/IP host within a network. The host address must be unique to the network ID. IPv4 Address Syntax An IP address consists of 32 bits. However, instead of using binary notation (Base2) to express IPv4 addresses 32 bits at a time, it is standard practice to segment the 32 bits of an IPv4 address into octets, which are four 8-bit fields. Each octet is converted to a decimal number (base 10) ranging from 0 (zero) to 255, and separated by a period (a dot). This format is called dotted decimal notation. The following section provides an example of an IP address in binary and dotted decimal formats. An IP Address in Binary and Dotted Decimal Formats Binary Format: Dotted Decimal Notation: For example, consider the IPv4 address of : The address is segmented into 8-bit blocks: Each block is converted to decimal: The adjacent octets are separated by a period: Note: The notation w.x.y.z is used when referring to a generalized IP address. (More notes on the next slide)

4: Configuring and Troubleshooting Network Connections
Whiteboard: Build a network diagram similar to the slide, and add in relevant IP addresses for devices and hosts. As you progress through the topics, add subnet masks, gateway addresses, and other elements. Discussion Prompt: Encourage the students to suggest valid IP addresses for your network diagram.

20687B What Is a Subnet Mask? 4: Configuring and Troubleshooting Network Connections A subnet mask specifies which part of an IPv4 address is the network ID and which is the host ID Network ID x w y z 192 168 1 Subnet mask 255 IP address 200 A subnet mask defines the parts of an IPv4 address that are the network ID and the host ID. Whiteboard: When you configure the TCP/IP protocol on a Microsoft Windows computer, the TCP/IP configuration settings will require an IP address and subnet mask, and may require a default gateway. Emphasize that to configure TCP/IP correctly, students must understand how TCP/IP networks are addressed and divided into networks and subnetworks. The TCP/IP protocol uses the subnet mask to determine whether a host is on the local subnet or a remote network. In TCP/IP, the parts of the IP address that are used as the network and host addresses are not fixed, so you cannot determine the network and host addresses unless you have more information. The 32-bit subnet mask supplies this information. In the example above, the subnet mask is It is not obvious what this number means unless you know that 255 in binary notation equals The first 24 bits (the number of ones in the subnet mask) are identified as the network address, with the last 8 bits (the number of remaining zeros in the subnet mask) identified as the host address. Discussion Prompt: Ask your students to help you configure valid IP addresses based upon a network address and a subnet mask that you suggest.

What Is the Default Gateway?
20687B What Is the Default Gateway? 4: Configuring and Troubleshooting Network Connections A default gateway is a device, usually a router, on a TCP/IP internetwork that forwards IP packets to other subnets Router Default gateway Subnet 2 Windows 8 clients Subnet 1 A default gateway is a device, usually a router, on a TCP/IP internetwork that forwards IP packets to other subnets. Whiteboard: Draw a LAN, metropolitan area network (MAN), and wide area network (WAN) with IP ranges for each network, and use it for the discussion. If a TCP/IP computer needs to communicate with a host on another network, it typically communicates through a router. In TCP/IP terms, a default gateway occurs when you specify a host’s router , which links the host's subnet to other networks. This section explains how TCP/IP determines whether or not to send packets to its default gateway to reach another computer or device on the network. When a host attempts to communicate with another device using TCP/IP, it performs a comparison process using the defined subnet mask and the destination IP address versus the subnet mask and its own IP address. The result of this comparison tells the computer whether the destination is a local or remote host. If the result of this process determines the destination to be a local host, then the computer simply sends the packet on the local subnet. If the result of the comparison determines the destination to be a remote host, then the computer forwards the packet to the default gateway defined in its TCP/IP properties. The router then is responsible for forwarding the packet to the correct subnet. Discussion Prompt: Ask your students to help you configure valid gateway addresses based on various subnets in a LAN, MAN, and WAN network that you have drawn on the whiteboard. Additional information: Emphasize that without a gateway address, IPv4 computers cannot communicate outside their local subnet.

What Are Public and Private IPv4 Addresses?
4: Configuring and Troubleshooting Network Connections Private Nonroutable on the Internet Can be assigned locally by organization Must be translated to access the Internet Public Required by devices and hosts that connect directly to the Internet Must be unique Routable on the Internet Must be assigned by IANA Devices and hosts that connect directly to the Internet require a public IPv4 address. However, hosts and devices that do not connect directly to the Internet do not. Whiteboard: Write the private IP address ranges on the board. If your intranet is not connected to the Internet, you can deploy any IP addressing. However, if you require direct (routed) or indirect (proxy or translator) connectivity to the Internet, there are two types of addresses you can use: public and private. Public Addresses Public addresses are assigned by the Internet Corporation for Assigned Names and Numbers (ICANN) and consist of class-based network IDs or blocks of CIDR-based addresses, which also are known as CIDR blocks. Public addresses are guaranteed to be globally unique to the Internet. When the public addresses are assigned, routes are programmed into the Internet’s routers so that traffic to the assigned public addresses can reach their locations. Traffic to destination public addresses is reachable on the Internet. For example, when an organization is assigned a CIDR block in the form of a network ID and subnet mask, the [network ID, subnet mask] pair exists as a route in the Internet’s routers. IP packets destined to an address within the CIDR block are routed to the proper destination. Private Addresses Each IP node requires an IP address that is globally unique to the IP internetwork. In the case of the Internet, each IP node on a network that connects to the Internet requires an IP address that is globally unique to the Internet. As the Internet grew, organizations connecting to the Internet required a public address for each node on their intranets. This placed a huge demand on the pool of available public addresses. When analyzing the addressing needs of organizations, the designers of the Internet noted that for many organizations, most of the hosts on the organization's intranet did not require direct connectivity to Internet hosts. Those hosts that did require a specific set of Internet services, such as the World Wide Web access and , typically access the Internet services through application layer gateways, such as proxy and servers. The result is that most organizations only required a small number of public addresses for those nodes (such as proxies, routers, firewalls, and translators) that connected directly to the Internet. (More notes on the next slide)

Hosts within the organization that do not require direct access to the Internet so require IP addresses that do not duplicate public addresses that are assigned already. To solve this addressing problem, the Internet designers reserved a portion of the IP address space, and named this space the private address space. An IP address in the private address space is known as a private address, and is never assigned as a public address. Devices that use a private address communicate to the Internet through a device that performs network address translation (NAT). The NAT device translates the IP addresses in the headers of the network packets before transmission onto the Internet. This enables many computers to use the same private IP addresses, because the public and private address spaces do not overlap, and private addresses never duplicate public addresses. The following three address blocks define the private address space that RFC 1918 specifies: /8: The /8 private network is a class A network ID that includes the following range of valid IP addresses: to The /8 private network has 24 host bits that can be used for any subnetting scheme within the private organization. /12: The /12 private network can be interpreted either as a block of 16 class B network IDs or as a 20-bit assignable address space (20 host bits) that can be used for any subnetting scheme within the private organization. The /12 private network includes the following range of valid IP addresses: to /16: The /16 private network can be interpreted either as a block of 256 class C network IDs or as a 16-bit assignable address space (16 host bits) that can be used for any subnetting scheme within the private organization. The /16 private network includes the following range of valid IP addresses: to (More notes on the next slide)

The result of many organizations using private addresses is that the private address space is reused, and this helps to prevent the depletion of public addresses. Because the IP addresses in the private address space will never be assigned by ICANN as public addresses, there will never exist routes in the Internet routers for private addresses. Private addresses are not reachable on the Internet. Therefore, Internet traffic from a host that has a private address must either send its requests to an application layer gateway with a valid public address, such as =a proxy server, or have its private address translated into a valid public address by a network address translator (NAT) before it is sent on the Internet. Discussion Prompt: Ask students what IP address they use at home. Ask students to determine the IP address of their classroom host computer. Additional information: Mention that Classless Interdomain Routing (CIDR) was introduced to slow the growth of routing tables and routers across the internet, in IPv4. Additional Reading: For additional information on CIDR, go to Question Which of the following is not a private IP address? a b c d Answer A and B. C and D are private IP addresses. C falls in the range of to , and D falls in the range of to

Demonstration: Configuring an IPv4 Address
20687B Demonstration: Configuring an IPv4 Address 4: Configuring and Troubleshooting Network Connections In this demonstration, you will see how to configure a Windows 8 computer with: An IPv4 address A subnet mask A default gateway Preparation Steps Start the 20687B-LON-DC1 virtual machine. Then start the 20687B-LON-CL1 virtual machine. Demonstration Steps View the current network connection configuration Sign in to the LON-CL1 virtual machine as Adatum\Administrator with the password Pa$$w0rd. On the Start screen, right-click the display, click All apps, and then click Command Prompt. At the command prompt, type ipconfig /all, and then press Enter. This displays the configuration for all network connections on the computer. Close the command prompt. View the IPv4 configuration Point to the bottom-left corner of the taskbar, and then click Start to return to the Start screen. Point to the lower-right corner of the Start screen, and then click Search. In the Search box, type Control, and then click Control Panel. In Control Panel, click Network and Internet. In Network and Internet, click View network status and tasks. In Network and Sharing Center, to the right of the Adatum.com Domain network, click Local Area Connection. In the Local Area Connection Status window, click Details. This window shows the same configuration information for this adapter as the ipconfig command. In the Network Connection Details windows, click Close. In the Local Area Connection Status window, click Properties. You can configure protocols in this window. (More notes on the next slide)

Click Internet Protocol Version 4 (TCP/IPv4), and then click Properties. You can configure the IP address, subnet mask, default gateway, and Domain Name System (DNS) servers in this window. Click Advanced. In the Advanced TCP/IP Settings window, you can configure additional settings, such as additional IP addresses, DNS settings, and Windows Internet Naming Service (WINS) servers for NetBIOS name resolution. Close all open windows without modifying any settings. Question When might you need to change a computer’s IPv4 address? Answer You might need to change a computer’s IPv4 address when two computers have the same IPv4 address. You must ensure that all computers on your network have a unique IPv4 address. If two computers have the same IPv4 address, then you must change the IPv4 address on one of the two computers.

Lesson 2: Configuring IPv6 Network Connectivity
20687B Lesson 2: Configuring IPv6 Network Connectivity 4: Configuring and Troubleshooting Network Connections IPv6 Addresses This lesson’s key focus is to explain the IPv6 addressing scheme and to show how to configure Windows 8 computers on an IPv6 network. Support for IPv6, a new suite of standard protocols for the network layer of the Internet, is built into the latest versions of Microsoft Windows, which include Windows 7, Windows 8, Windows Server 2012, Windows Server® 2008 R2, Windows Server 2008, Windows Vista®, Windows Server 2003, Windows XP® with Service Pack 2 (SP2), Windows XP with Service Pack 1 (SP1), Windows XP Embedded SP1, and Windows CE .NET. With Windows Server 2008 R2 and Windows 8, Microsoft continues its platform-wide support for IPv6 with a protocol stack that supports industry standards, and built-in applications and services. As with Windows Vista and Windows Server 2008, IPv6 in Windows Server 2008 R2 and Windows 8 is installed and enabled by default. IPv6 is designed to solve many of the problems of the current version of IP (known as IPv4), such as address depletion, security, autoconfiguration, and extensibility. Its use also will expand the capabilities of the Internet to enable a variety of valuable and exciting scenarios, including peer-to-peer and mobile applications. Most students will be unfamiliar with this content, although some will have had some exposure. Gauge the experience level of your students carefully when delivering this lesson, because it can be confusing for students without any IPv6 experience.

Benefits of Implementing IPv6
4: Configuring and Troubleshooting Network Connections Benefits of IPv6 include: Large address space Hierarchical addressing and routing infrastructure Stateless and Stateful address configuration Required support for IPsec Restored end-to-end communication Prioritized delivery New protocol for neighboring node interaction Extensibility The new IPv6 features and functionality address many of IPv4 limitations. Additionally, the IPv6 enhancements also enable easier and more secure communication on the Internet and over corporate networks. An IPv6 address is four times as large as an IPv4 address. The global addresses used on the IPv6 portion of the Internet create an efficient, hierarchical, and summarized routing infrastructure that addresses the common occurrence of multiple levels of Internet service providers. On the IPv6 Internet, the backbone routers have an efficient and hierarchical addressing and routing infrastructure that uses smaller routing tables. IPv6 supports both stateful address configuration (such as address configuration in the presence of a DHCP server) and stateless address configuration (address configuration in the absence of a DHCP server). The support for IPsec is an IPv6 protocol suite requirement. This requirement provides a standards-based solution for network security needs and promotes interoperability between different IPv6 implementations. The new format of the IPv6 header is designed to minimize header validation and processing. Additionally, a new field in the IPv6 header helps to define how traffic is handled and identified for quality-of-service delivery. IPv6 can be extended for new features by adding extension headers after the IPv6 header. Unlike the IPv4 header, which can only support 40 bytes of options, only the size of the IPv6 packet constrains s the size of the IPv6 extension headers. The new Neighbor Discovery protocol in IPv6 is a series of Internet Control Message Protocol for IPv6 (ICMPv6) messages that manage the interaction of neighboring nodes. Neighbor Discovery replaces Address Resolution Protocol (ARP), ICMPv4 Router Discovery, and ICMPv4 Redirect messages with efficient multicast and unicast messages. Discussion Prompt: Ask students if they have experience using IPv6. (More notes on the next slide)

Additional information: IPv6 is designed to solve many of the problems of the current version of IP (known as IPv4) such as address depletion, security, autoconfiguration, and extensibility. Its use will also expand the capabilities of the Internet to enable a variety of valuable and exciting scenarios, including peer-to-peer and mobile applications. Additional Reading: For more information on IPv6, go to

Windows 8 Support for IPv6
20687B Windows 8 Support for IPv6 4: Configuring and Troubleshooting Network Connections IPv6 is Enabled by Default Windows 8 uses IPv6 by default to support security needs and additional features Windows 8 Dual Stack Windows 8 facilitates the dual stack to use IPv4 and IPv6 simultaneously Direct Access requires IPv6 Windows 8 clients can use DirectAccess, which facilitates client computers connecting to the enterprise domain Remote Desktop uses IPv6 IPv6 supports Windows 8 File Sharing Security and Echo System features, such as Remote Access and DirectAccess Windows 8 provides features like DirectAccess, BranchCache®, and VPN Reconnect. Cover the following features at a high level: The Win8 dual stack. How IPv6 is enabled by default. How services, such as file sharing and remote desktop, can use IPv6. How DirectAccess requires IPv6.

IPv6 Addresses IPv6 Address Types
20687B IPv6 Addresses 4: Configuring and Troubleshooting Network Connections IPv6 Address Types Unicast – use for one-to-one communication between hosts Multicast – use for one-to-many communication between computers that are defined as using the same multicast address Anycast – use for locating services or the nearest router Important: Based on your students’ experience, present as little or as much of this content as you think appropriate. IPv6 has three types of addresses, categorized by type and scope: Unicast addresses: A packet is delivered to one interface. Multicast addresses: A packet is delivered to multiple interfaces. Anycast addresses: A packet is delivered to the nearest of multiple interfaces (in terms of routing distance). IPv6 does not use broadcast messages. Unicast and anycast addresses in IPv6 have the following scopes (for multicast addresses, the scope is built into the address structure): Link-local: The scope is the local link (nodes on the same subnet). Site-local: The scope is the organization (private site addressing). Global: The scope is global (IPv6 Internet addresses). Additionally, IPv6 has special addresses, such as the loopback address. The scope of a special address depends on its type. Much of the IPv6 address space is unassigned. IPv6 unicast site-local addresses are similar to IPv4 private addresses. The scope of a site-local address is the internetwork of an organization’s site, and you can use both global addresses and site-local addresses in your network. The prefix for site-local addresses is FEC0::/48. The initial 48 fixed bits are followed by a 16-bit Subnet ID field, which provides as many as 65,536 subnets in a flat subnet structure. Alternatively, you can subdivide the high-order bits of the Subnet ID field to create a hierarchical routing infrastructure. The last field is a 64-bit Interface ID field that identifies the interface of a node on a specific subnet. IPv6 Unicast Address Types Global Unicast – globally routable and reachable on the IPv6 portion of the Internet Link-Local – use when communicating with neighboring hosts on the same link Unique Local Unicast – equivalent to IPv4 private address spaces (More notes on the next slide)

Note: Global addresses and site-local addresses share the same structure after the first 48 bits--the 16-bit Site Level Aggregator ID of a global address and the 16-bit Subnet ID of a site-local address both identify the subnets of an organization’s site. Because of this, you can assign a specific subnet number to identify a subnet that is used for both global and site-local unicast addresses. Unicast Link-local Addresses (FE80::/64) IPv6 unicast link-local addresses are similar to IPv4 APIPA addresses used by computers running Microsoft Windows. Hosts on the same link (the same subnet) use these automatically configured addresses to communicate with each other. Neighbor Discovery provides address resolution. The prefix for link-local addresses is FE80::/64. Unicast Unspecified Address The IPv6 unicast unspecified address is equivalent to the IPv4 unspecified address of The IPv6 unspecified address is 0:0:0:0:0:0:0:0:, or a double colon (::). Unicast Loopback Address The IPv6 unicast loopback address is equivalent to the IPv4 loopback address, The IPv6 loopback address is 0:0:0:0:0:0:0:1, or ::1. Unicast 6to4 Addresses (2002::/16) IPv6 uses 6to4 addresses to communicate between two IPv6/IPv4 nodes over the IPv4 Internet. A 6to4 address combines the prefix 2002::/16 with the 32 bits of the public IPv4 address of the node to create a 48-bit prefix — 2002:WWXX:YYZZ::/48, where WWXX:YYZZ is the colon-hexadecimal representation of w.x.y.z, a public IPv4 address. Therefore, the IPv4 address translates into a 6to4 address prefix of 2002:9D3C:5B7B::/48. However, this is often written using the hexadecimal prefix: 2002:WWXX:YYZZ:SLA ID:Interface ID. Unicast ISATAP Addresses IPv6 uses Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) addresses to communicate between two IPv6/IPv4 nodes over an IPv4 intranet. An ISATAP address combines a 64-bit unicast link-local, site- local, or global prefix (a global prefix might be a 6 to 4 prefix) with a 64-bit suffix constructed of the ISATAP identifier 0:5EFE, followed by the IPv4 address assigned to one of the host’s interfaces. The prefix is (More notes on the next slide)

known as the subnet prefix. Although a 6to4 address can incorporate only a public IPv4 address, an ISATAP address can incorporate either a public or a private IPv4 address. Multicast IPv6 Addresses IPv6 multicast addresses are similar to IPv4 multicast addresses. Packets addressed to a multicast address are delivered to all interfaces that the address identifies. Multicast Solicited Node Address The IPv6 multicast solicited node address is used for efficient address resolution. The IPv4 ARP Request frame is sent to the MAC-level broadcast, which disturbs all nodes on the network segment. The multicast solicited node address combines the prefix FF02::1:FF00:0/104 with the last 24 bits of the IPv6 address being resolved. IPv6 uses the solicited node multicast address for the Neighbor Solicitation message, which is the IPv6 equivalent to the ARP Request frame. This message resolves an IPv6 address to its link- layer address, disturbing few nodes during the address resolution process. Anycast IPv6 Addresses Anycast IPv6 addresses are similar to, but more efficient than, the anycast addresses in IPv4, which primarily large ISPs use. Anycast addresses use the unicast address space, but function differently from other unicast addresses. IPv6 uses anycast addresses to identify multiple interfaces. IPv6 delivers packets addressed to an anycast address to the nearest interface that the address identifies. In contrast to a multicast address, where delivery is from one to many, an anycast address delivery is from one to one-of- many. Currently, anycast addresses are assigned only to routers and used only as destination addresses. Whiteboard: Write examples of each address type on the board while you discuss them. Discussion Prompt: Ask the students to compare the IPv4 equivalents of the IPv6 address types. For example, ask the students to tell you the IPv4 equivalent of an IPv6 link-local address. Additional Reading: For 6 more information on IPv6 address types, go to

Lesson 3: Implementing Automatic IP Address Allocation
20687B Lesson 3: Implementing Automatic IP Address Allocation 4: Configuring and Troubleshooting Network Connections Troubleshooting Client-Side IPv4 Autoconfiguration Issues This lesson’s key focus is to explain that Windows 8 enables both the IPv4 and IPv6 protocols to obtain their configuration automatically. An IP address is an identifier that is assigned at the Internet layer to an interface or a set of interfaces. Each IP address can identify the source or destination of IP packets. For IPv4, every node on a network has one or more interfaces, and you can enable TCP/IP on each of those interfaces. When you enable TCP/IP on an interface, you assign it one or more logical IPv4 addresses, either automatically or manually. DHCP is a TCP/IP standard that reduces the complexity and administrative overhead of managing network client IP address configuration. Microsoft Windows Server provides the DHCP service, which enables a computer to function as a DHCP server and configure DHCP-enabled client computers on your network. DHCP runs on a server computer, enabling the automatic, centralized management of IP addresses and other TCP/IP configuration settings for your network's client computers. The Microsoft DHCP service also provides integration with the Active Directory® Domain Services (AD DS) and DNS service, enhanced monitoring and statistical reporting for DHCP servers, vendor-specific options and user-class support, multicast address allocation, and rogue DHCP server detection. The Dynamic Host Configuration Protocol version 6 (DHCPv6) Server service is a process that runs in the background on a computer that is running Windows Server and that provides IPv6 addresses to clients.

Automatic IPv4 Configuration
20687B Automatic IPv4 Configuration 4: Configuring and Troubleshooting Network Connections IPv4 Client DHCP Server with IPv4 Scope IPv4 Router IPv4 Static Configuration Students should be able to identify when a service allocates an IP address automatically, and when the system self-configures an IP address, as in Automatic Private IP Addressing (APIPA) and link-local addresses. Discussion Prompt: Ask students if they recognize the IP address On IPv4 networks, addresses can be assigned to hosts in three ways: Manually, by using static address assignment. Automatically, by using DHCP, if a DHCP server is present on the subnet (or a DHCP relay agent configured on the subnet). Automatically, by using APIPA, which randomly assigns the host an address from the range to with subnet mask DHCPv4 provides an automated way to distribute and update IP addresses and other configuration information on a network. A DHCP server provides this information to a DHCP client through the exchange of a series of messages, known as the DHCP conversation or the DHCP transaction. If the DHCP server and DHCP clients are located on different subnets, a DHCP relay agent facilitates the conversation. The DHCP architecture consists of DHCP clients, DHCP servers, and DHCP relay agents on a network. The clients interact with servers using DHCP messages in a DHCP conversation to obtain and renew IP address leases. DHCP Client Functionality A DHCP client is any network-enabled device that supports communication with a DHCP server in compliance with RFC 2131, for the purpose of obtaining dynamic-leased IP configuration and related optional information. Automatic IP Configuration DHCP supports APIPA, which enables computers to configure an IP address and subnet mask if a DHCP server is unavailable at system startup and the Automatic private IP address Alternate Configuration setting is selected. (More notes on the next slide)

How a Client Obtains an IP Configuration The DHCP Client service uses the following process to auto-configure the client: The DHCP client attempts to locate a DHCP server and obtain an IP address and configuration. If a DHCP server cannot be found or does not respond after one minute, the DHCP client checks the settings on the Alternate Configuration tab of the TCP/IP protocol’s properties. If Automatic private IP address is selected, the DHCP client autoconfigures its IP address and subnet mask by using a selected address from the Microsoft-reserved Class B network, , with the subnet mask The DHCP client tests for an address conflict to ensure that the IP address is not in use on the network. If a conflict is found, the client selects another IP address. The client retries auto-configuration up to 10 times. If User Configured is selected, the DHCP client configures a static IP address configuration. The DHCP client tests for an address conflict to ensure that the IP address is not already in use on the network. If a conflict is found, the DHCP client indicates the error condition to the user. When the DHCP client succeeds in self-selecting an address, it configures its network interface with the IP address. The client then continues to check for a DHCP server in the background every five minutes. If a DHCP server responds, the DHCP client abandons its self-selected IP address and uses the address offered by the DHCP server (and any other DHCP option information that the server provides) to update its IP configuration settings. If the DHCP client obtained a lease from a DHCP server on a previous occasion, and the lease is still valid (not expired) at system startup, the client tries to renew its lease. If, during the renewal attempt, the client fails to locate any DHCP server, it attempts to ping the default gateway listed in the lease, and proceeds in one of the following ways: If the ping is successful, the DHCP client assumes that it is located on the same network where it obtained its current lease, and continues to use the lease as long as the lease is valid. By default, the client then attempts, in the background, to renew its lease when 50 percent of its assigned lease time has expired. If the ping fails, the DHCP client assumes that it has been moved to a network where a DHCP server is not available. The client then auto-configures its IP address by using the settings on the Alternate Configuration tab. When the client is auto-configured, then every five minutes, it attempts to locate a DHCP server and obtain a lease.

Automatic IPv6 Configuration
20687B Automatic IPv6 Configuration 4: Configuring and Troubleshooting Network Connections Automatic IPv6 Configuration Process DHCPv6 Server. Assigns Automatic IPv6 Configuration information to the client Students must understand the key IPv6 autoconfiguration states. The main points that you should cover include: There are several states in which the host can reside as it goes through autoconfiguration, and =there are several ways that you can assign an IP address and related information. Based on how you set up the router, a client might need to use stateless configuration (no DHCP service), or stateful configuration with a DHCP server involved, to either assign an IP address and other information, or just assign other information. The other information includes DNS servers. Note that the gateway address is not assigned from a DHCP server, but always via router solicitation. The example in this slide is the simplified process if the network is using an IPv6 router with additional prefixes and a DHCP server to configure a stateful address. IPv6 Client. Uses DHCP-assigned IP Configuration to access network resources IPv6 Static Client. Does not get automatic configuration from the DHCPv6 Server IPv6 Router. Provides a Gateway to the Internet or another Subnet

20687B Demonstration: Configuring a Computer to Obtain an IPv4 Configuration Automatically 4: Configuring and Troubleshooting Network Connections In this demonstration, you will see how to: Automatically configure a Windows 8 computer with an IPv4 address Verify the IP configuration Preparation Steps The required virtual machines, 20687B-LON-DC1 and 20687B-LON-CL1, should already be running after the preceding demonstration. Demonstration Steps View the current IPv4 configuration If necessary, sign in to the LON-CL1 virtual machine as Adatum\Administrator with the password Pa$$w0rd. If necessary, point to the bottom-left corner of the taskbar, and then click Start to return to the Start screen. On the Start screen, right-click the display, click All apps, and then click Command Prompt. At the command prompt, type ipconfig /all, and then press Enter. This displays the configuration for all network connections on the computer. Close the command prompt. Reconfigure the IPv4 configuration Point to the bottom-left corner of the taskbar, and then click Start to return to the Start screen. Point to the lower-right corner of the desktop, and then click Search. In the Search box, type Control, and then click Control Panel. In Control Panel, click Network and Internet. In Network and Internet, click View network status and tasks. In Network and Sharing Center, to the right of the Adatum.com Domain network, click Local Area Connection. In the Local Area Connection Status window, click Properties. In this window, you can configure protocols. (More notes on the next slide)

Click Internet Protocol Version 4 (TCP/IPv4), and then click Properties. Click Obtain an IP address automatically. Notice that the Alternate Configuration tab becomes available when you do this. Click Obtain DNS server address automatically. Click the Alternate Configuration tab. Configuration information on this tab is used when no Dynamic Host Configuration Protocol (DHCP) server is available. Click OK to save the changes. In the Local Area Connection Properties window, click Close. In the Local Area Connection Status window, click Details. Notice that DHCP is enabled and the IP address of the DHCP server is displayed. Close all open windows.

Troubleshooting Client-Side IPv4 Autoconfiguration Issues
4: Configuring and Troubleshooting Network Connections IPConfig is used to display IP configuration information and to release and renew addresses The IPConfig tool is the primary client-side DHCP troubleshooting tool. Demonstration: Show the students the various troubleshooting options. Use the currently running virtual machine environment. Reference Links: Test a TCP/IP configuration by using the ping command: Verify, release, or renew a client address lease: Configure TCP/IP for automatic addressing: Disable automatic address configuration: Manage Options and classes: Assigning options: DHCP Best Practices: Using superscopes: Option Description /all Displays all IP address configuration information /release Releases a dynamic IPv4 address lease /renew Renews a dynamic IPv4 address lease (More notes on the next slide)

Configuring scopes:

Lab A: Configuring a Network Connection
4: Configuring and Troubleshooting Network Connections Exercise 2: Configuring IPv4 Manually Exercise 1: Enabling Automatic IPv4 Configuration Exercise 2: Configuring IPv4 Manually Logon Information Virtual Machines B-LON-DC1 20687B-LON-CL1 User Name Adatum\Administrator Password Pa$$w0rd Estimated Time: 30 minutes

20687B Lab Scenario 4: Configuring and Troubleshooting Network Connections A. Datum Corporation is introducing new laptop computers for some of the managers in A. Datum Corporation. You need to test how the IPv4 configuration will behave when the managers are away from the office and a DHCP server is unavailable.

20687B Lab Review 4: Configuring and Troubleshooting Network Connections How can you update a Windows 8 computer to use the correct information after a host record is updated in DNS, but the Windows 8 computer is still resolving the name to the previous IP address? Question How are APIPA addresses for IPv4 similar to link-local addresses in IPv6? Answer Both APIPA addresses are designed to allow computers to communicate on the local network automatically without the use of a DHCP server or any other IP address configuration. However, an APIPA address is only used when a DHCPv4 server is unavailable. An IPv6 link-local address is always generated for a host using IPv6. Additional IPv6 addresses can still be obtained for communication outside the local network. How can you update a Windows 8 computer to use the correct information after a host record is updated in DNS, but the Windows 8 computer is still resolving the name to the previous IP address? When a computer resolves a name to an IP address by using DNS, the name and IP address are cached locally. You can clear this cache at a command prompt with the command ipconfig /flushdns.

Lesson 4: Implementing Name Resolution
20687B Lesson 4: Implementing Name Resolution 4: Configuring and Troubleshooting Network Connections Methods for Resolving Computer Names This lesson’s key focus is on how a name can be an alternative to an IP address when identifying computers on a network. This lesson has two topics regarding different types of computer names to use and the methods for resolving computer names. After completing this lesson, you will be able to: Describe the types of names used by IPv4 computers. Describe how name resolution works.

Types of Computer Names
20687B Types of Computer Names 4: Configuring and Troubleshooting Network Connections Name Description Host name Up to 255 characters in length Can contain alphanumeric characters, periods, and hyphens Part of FQDN NetBIOS name Represents a single computer or group of computers 15 characters used for the name 16th character identifies service Flat namespace NetBIOS over TCP/IP is the network component that performs mapping of computer names to IP addresses, and name resolution. There are currently four NetBIOS over TCP/IP name resolution methods: b-node, p-node, m-node, and h-node. Additionally, Windows uses WINS, b-node broadcasts, and the LMHOSTS file for NetBIOS name resolution. If all of these name resolution methods are used, an h-node host computer implements them in the following order: NetBIOS name cache WINS server B-node broadcast LMHOSTS file HOSTS file DNS server Note: This setting and the name-resolution order above apply only to NetBIOS name resolution. Any Winsock name-resolution queries the HOSTS file and assigns DNS servers first. When you access a LAN, an intranet share, or an intranet website by using an IP address or a FQDN, the share or website may be identified as in the Internet zone instead of in the Local intranet zone. For example, this behavior may occur if you access shares or websites with Windows Internet Explorer®, with Microsoft Windows Explorer, with a command prompt, or with a Windows-based program when you use an address in any one of the following formats: \\Computer.childdomain.domain.com\Share \\ \share file:// /share

Methods for Resolving Computer Names
20687B Methods for Resolving Computer Names 4: Configuring and Troubleshooting Network Connections Broadcast 7 2 Local Host Name 1 Lmhosts File 8 DNS Server 4 WINS Server 6 NetBIOS Name Cache 5 Hosts file 3 2 DNS Resolver Cache Name resolution is an essential part of computer networking because it is easier for users to remember names than abstract numbers, such as an IPv4 address. Discussion Prompt: Ask students if they are familiar with NetBIOS naming. Demonstration: Display the host and NetBIOS names of the virtual machine. Additional information: Ensure that students understand that NetBIOS and Windows Internet Naming Service (WINS) are legacy components. Ensure that students are familiar with the different types of names. Host Name A host name is a user-friendly name that is associated with a host’s IP address and identifies it as a TCP/IP host. A host name can be no more than 255 characters in length and contains alphanumeric characters, periods, and hyphens. A host name is an alias or a fully qualified domain name (FQDN). An alias is a single name associated with an IP address. The host name combines an alias with a domain name to create the FQDN. The elements of the name include periods as separators. Applications use the structured FQDN on the Internet. An example of an FQDN is payroll.contoso.com. NetBIOS Name Applications use the 16-character NetBIOS name to identify a NetBIOS resource on a network. A NetBIOS name represents a single computer or a group of computers. NetBIOS uses the first 15 characters for a specific computer’s name and the final sixteenth character to identify a resource or service on that computer. An example of a NetBIOS name is NYC-SVR2[20h]. (More notes on the next slide)

Windows supports a number of different methods for resolving computer names, such as DNS, WINS, and the host-name resolution process. Name Resolution When discussing the name-resolution process, show the students how names are resolved. Start by writing down the various methods, and then demonstrate each method by using the virtual machine environment. Include insertion of entries into HOSTS and using tools such as Nslookup, or the Resolve- DnsName Windows PowerShell Cmdlet. It is important that students know in which order name-resolution methods are attempted. Name Resolution with WINS WINS is required for the following reasons: Older versions of Microsoft operating systems rely on WINS for name resolution. Some applications, typically older ones, rely on NetBIOS names. You need dynamic registration of single-label names. Users rely on the Network Neighborhood or My Network Places network browser features. You are not using Windows Server 2008 or higher as your DNS infrastructure. Deciding if you need to deploy a GlobalNames zone Consider deploying a GlobalNames zone if: You are retiring WINS or you are planning to deploy only IPv6 in your environment, so that all name resolution will depend on DNS. Your need for single-label name resolution is limited to important servers or websites that can be statically registered in DNS. Typically, these names also are configured statically and globally in the WINS database. Host names cannot be registered in the GlobalNames zone by dynamic updates. (More notes on the next slide)

You cannot rely on the suffix search lists on client computers to provide single-label name resolution. This may be because the number of target domains is too great or the domains cannot be centrally managed to guarantee that host names will be unique. All the DNS servers that are authoritative for your zones must be servers that are running Windows Server 2008. To resolve names that are registered in the GlobalNames zone, all DNS servers that are authoritative for a zone and that serve client query requests must be running Windows Server 2008, and they must either be configured with a local copy of the GlobalNames zone or they must be able to contact remote DNS servers that host the GlobalNames zone. We also recommend that the GlobalNames zone be integrated with AD DS. This integration with AD DS ensures easier management and future scalability. Additional Reading: To read more about understanding DNS client settings on TechNet, go to

Lesson 5: Troubleshooting Network Connectivity
4: Configuring and Troubleshooting Network Connections Demonstration: Troubleshooting Common Network Issues Use demonstrations in each topic, aside from the formal demonstration, to reinforce this content.

Tools for Troubleshooting Network Issues
4: Configuring and Troubleshooting Network Connections Tool Purpose Event Viewer Enables you to view errors relating to network activity Windows Network Diagnostics Helps to diagnose and resolve network problems IPCONFIG Displays IP configuration information and controls the DNS resolver cache PING and PathPING Verifies basic IP connectivity TRACERT Verifies a routing path NSLOOKUP Enables testing of name resolution Windows PowerShell Enables you to configure and troubleshoot network-related settings Network Monitor Enables you to capture and analyze network traffic List each tool, and describe its purpose. Event Viewer lets you view and set logging options for event logs to gather information about hardware, software, and system problems. The Windows Network Diagnostics for Windows 8 tool analyzes information about your network connectivity to help you troubleshoot network-related problems with your computer. Typically you will do this along with a support professional, either on the phone or over the Internet. After you install this item, you may have to restart your computer. IPConfig.exe is a utility included with Windows 8. The purpose of this utility is to provide the user with diagnostic information related to the TCP/IP network configuration. IPConfig also accepts various DHCP commands, enabling a system to update or release its TCP/IP network. The ping command helps to verify IP-level connectivity. When troubleshooting, you can use ping to send an ICMP echo request to a target host name or IP address. Use ping whenever you need to verify that a host computer can connect to the TCP/IP network and network resources. You also can use ping to isolate network hardware problems and incompatible configurations. Pathping provides information about network latency and network loss at intermediate hops between a source and destination. Pathping sends multiple Echo Request messages to each router between a source and destination over a period of time and then computes results based on the packets returned from each router. Because pathping displays the degree of packet loss at any given router or link, you can determine which routers or subnets might be having network problems. Pathping performs the equivalent of the tracert command by identifying which routers are on the path. It then sends pings periodically to all of the routers over a specified time period, and computes statistics based on the number returned from each. Used without parameters, pathping displays help. Windows PowerShell has cmdlets for configuring and troubleshooting network settings. Consider demonstrating each of the listed Cmdlets. Network Monitor allows you to capture and analyze network traffic. Discussion Prompt: Ask students to recommend a network-troubleshooting tool for the situations that you suggest. (More notes on the next slide)

Tracert is a route-tracing utility that displays a list of near-side router interfaces of the routers along the path between a source host and a destination. Tracert uses the IP TTL field in ICMP Echo Requests and ICMP Time Exceeded messages to determine the path from a source to a destination through an IP internetwork. Nslookup.exe is a command-line administrative tool for testing and troubleshooting DNS servers. This tool is installed along with the TCP/IP protocol through Control Panel. Demonstration: Although you are about to perform a demonstration, you might like to show a brief demonstration of each tool in use at this point. Additional Reading: For more information, go to Microsoft Support at

Process for Troubleshooting Network Issues
4: Configuring and Troubleshooting Network Connections IPConfig Nslookup or Get-DNSname Tracert Ping Windows Network Diagnostics Event Viewer Discuss the troubleshooting process. Discussion Prompt: Ask students to add to their last discussion topic regarding their recommendation of a network- troubleshooting process for the situations that you suggest.

Demonstration: Troubleshooting Common Network Issues
4: Configuring and Troubleshooting Network Connections In this demonstration, you will see how to use the TCP/IP troubleshooting tools to help resolve common connectivity problems Preparation Steps The required virtual machines, 20687B-LON-DC1 and 20687B-LON-CL1, should already be running after the preceding demonstration. Demonstration Steps Verify the current network connection settings If necessary, sign in to the LON-CL1 virtual machine as Adatum\Administrator with the password Pa$$w0rd. Use IPConfig to troubleshoot the network connections If necessary, point to the lower-left corner of the taskbar, and then click Start. On the Start screen, right-click the display, click All apps, and then click Command Prompt. At the command prompt, type ipconfig /all, and then press Enter. This displays the configuration for all network connections on the computer. At the command prompt, type ipconfig /displaydns, and then press Enter. This displays the contents of the DNS cache. At the command prompt, type ipconfig /flushdns, and then press Enter. This clears the contents of the DNS cache. Use Ping to troubleshoot the network connections At the command prompt, type ping , and then press Enter. This pings the local host. At the command prompt, type ping , and then press Enter. This verifies connectivity to LON-DC1 by using an IPv4 address. At the command prompt, type ping LON-DC1, and then press Enter. This verifies connectivity to LON-DC1 by using a host name. (More notes on the next slide)

Use Nslookup to troubleshoot name resolution At the command prompt, type nslookup –d1 LON-DC1, and then press Enter. This provides detailed information about the host name resolution. You can use the –d2 option for even more detail. Close the command prompt. Question How is the ping command useful for troubleshooting? Answer You can use the ping command to verify connectivity between hosts. Though the ping command can verify connectivity between hosts, be aware that firewalls can block ping packets but still allow the packets for other applications. If you obtain a response to a ping attempt, the host is definitely running. However, if you do not obtain a response to a ping attempt, the host may still be functional.

Lab B: Troubleshooting Network Connectivity
4: Configuring and Troubleshooting Network Connections Exercise 2: Resolving a Network Connectivity Problem Exercise 1: Creating a Simulated Network Connectivity Problem Exercise 2: Resolving a Network Connectivity Problem Virtual Machines B-LON-DC1 20687B-LON-CL1 User Name Adatum\Administrator Password Pa$$w0rd Logon Information Estimated Time: minutes

20687B Lab Scenario 4: Configuring and Troubleshooting Network Connections An intern has been unsuccessful in attempts to resolve a network connectivity problem on a Windows 8 computer. The changes made to the computer have not been documented. You need to restore network connectivity for the computer.

How did you resolve these two problems?
Lab Review 4: Configuring and Troubleshooting Network Connections How did you resolve these two problems? Question In the lab, what were the two problems that you encountered on the user’s computer? Answer The first problem was the IPv4 configuration; specifically, the subnet mask was incorrect. The second problem was the DNS configuration on the client was referencing an incorrect DNS server address, preventing name resolution. How did you resolve these two problems? Answers may vary, but students should have manually reconfigured the subnet mask and DNS server address.

Module Review and Takeaways
20687B Module Review and Takeaways 4: Configuring and Troubleshooting Network Connections Common Issues and Troubleshooting Tips Review Questions Question After starting her computer, Amy notices that she is unable to access her normal resources. What tool can she use to determine if she has a valid IP address? Answer Amy can run IPConfig /All or Ping her domain controller’s IP Address. When transmitting Accounts Receivable updates to the billing partner in China, Amy notices that the files are being transmitted slowly. What tool can she use to determine the network path and latency of the network? Amy can use Windows Diagnostics to identify the problem or use Pathping.exe to check for latency. Amy notices that she cannot access normal enterprise websites. She knows that she has a valid IP address but wants to troubleshoot the DNS access of her computer. What tool must she use? Amy can use Nslookup.exe to troubleshoot DNS access issues. What is the IPv6 equivalent of an IPv4 APIPA address? The IPv6 equivalent of IPv4 APIPA addresses are IPv6 link-local addresses. You are troubleshooting a network-related problem, and you suspect a name resolution issue. Before conducting tests, you want to purge the DNS resolver cache. How do you do that? (More notes on the next slide)

Answer Use IPCongfig /flushdns to clear the DNS Resolver Cache. Question You are troubleshooting a network-related problem. The IP address of the host you are troubleshooting is What is a possible cause of the problem? The DHCP server is unavailable. Tools You can use the following tools to troubleshoot network connectivity issues. Tool Description Network and Sharing Center The Network and Sharing Center informs you about your network and verifies whether your PC can successfully access the Internet. Then, it summarizes this info in the form of a Network Map. Netsh.exe A command that you can use to configure network properties from the command-line. Pathping.exe A command-line tool that combines the functionality of Ping and Tracert, and that you can use to troubleshoot network latency and provide information about path data. Nslookup.exe A command-line tool that you can use to test and troubleshoot DNS and name resolution issues. IPConfig.exe A general IP configuration and troubleshooting tool. Ping.exe A basic command-line tool that you can use for verifying IP connectivity. Tracert.exe Similar to Pathping, which provides information about network routes. Windows PowerShell Cmdlets available to view and configure network settings. (More notes on the next slide)

Common Issues and Troubleshooting Tips Common Issue: Windows 8 host cannot connect to a Microsoft SharePoint® 2010 site. Troubleshooting Tip: Use Windows Diagnostics to Identify the problem. Common Issue: Windows 8 host cannot access the database server. Troubleshooting Tip: Use IPConfig tool to view, renew or release an IP Address. Common Issue: Windows 8 Host cannot connect to the Internet. Troubleshooting Tip: Use Ping to test the connectivity to the DNS Server. Common Issue: DNS server is not resolving FQDNS correctly. Troubleshooting Tip: Use the flushdns option with IPConfig.

Configuring and Troubleshooting Network Connections

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