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Chapter 8 Administering TCP/IP Objectives Understand basic concepts about TCP/IP Configure TCP/IP on Windows Server 2003 Troubleshoot TCP/IP and network connectivity using various utilities Administer Dynamic Host Configuration Protocol (DHCP) in Windows Server 2003 Understanding TCP/IP
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Chapter 8 Administering TCP/IP
Objectives • Understand basic concepts about TCP/IP • Configure TCP/IP on Windows Server 2003 • Troubleshoot TCP/IP and network connectivity using various utilities • Administer Dynamic Host Configuration Protocol (DHCP) in Windows Server 2003
Understanding TCP/IP • Transmission Control Protocol/Internet Protocol (TCP/IP) • Suite of protocols and utilities used for • Network communication • Troubleshooting on local networks and the Internet
Understanding TCP/IP (Continued) • TCP/IP has become the most popular network protocol in use today, because • It is the protocol suite used for Internet-based communications • It is an open-standard, vendor-independent protocol • In Windows Server 2003 environments, Active Directory depends on TCP/IP and related services to function
The TCP/IP Protocol Stack • Transmission Control Protocol (TCP) • Operates at the transport layer • Responsible for the reliable transmission of data on a TCP/IP network • A connection-based protocol • User Datagram Protocol (UDP) • Functions at the transport layer • A connectionless protocol • Provides no guarantee of packet delivery • Provides speed advantages in the form of lower overhead
The TCP/IP Protocol Stack (Continued) • Address Resolution Protocol (ARP) • Works at the Internet layer • Responsible for mapping IP addresses to hardware media access control (MAC) addresses • Every Windows Server 2003 computer has an ARP cache that stores both dynamic and static entries • Internet Control Message Protocol (ICMP) • Operates at the network layer • Used to exchange network status and error information between two hosts
The TCP/IP Protocol Stack (Continued) • Internet Group Management Protocol (IGMP) • Operates at the network layer • Used to manage network and host information when a network application requires the use of multicasts to communicate • Internet Protocol (IP) • Operates at the Internet layer • Responsible for addressing and routing packets so that they are delivered to the correct host • A connectionless protocol
The TCP/IP Protocol Stack (Continued) • IPv4 • The current version of IP • Uses a 32-bit addressing scheme • IP addresses are generally represented using dotted-decimal notation • For example: 192.168.1.1 • A subnet mask • Used to determine which portion of an address represents the network and which portion represents a unique host on that network
Installing TCP/IP • TCP/IP is installed by default if • The network adapter is automatically detected during the installation of Windows Server 2003 • If TCP/IP is not installed during setup, it can be added afterward • Once TCP/IP has been installed, the network administrator can either • Manually configure addressing parameters, or • Implement dynamic addressing using DHCP
Configuring TCP/IP on Windows Server 2003 Computers • All hosts on a TCP/IP network require • An IP address • A subnet mask • Options for configuring IP addresses on workstations and servers • Configure each one manually with a static IP address • Configure computers to obtain an IP address automatically • Requires a DHCP server on the network
Configuring Static IP Addresses • The decision on whether to use a static or dynamic IP-addressing method is often a function of the size of the network • For each network card configured to use TCP/IP, you must configure • An IP address • A subnet mask • TCP/IP Properties dialog box • Can be used to configure an IP address and a subnet mask
Configuring IP Addresses Dynamically • Dynamic IP addressing • Possible if there is a server on the network running DHCP • Advantages • Can eliminate some administrative problems associated with configuring static IP addresses, such as • The chance of human error • IP address duplication • A DHCP server is configured with a range of IP addresses that will be assigned to clients on the network
Automatic Private IP Addressing • Automatic private IP addressing (APIPA) • Allows DHCP-enabled clients to assign themselves an IP address and subnet mask in the event that a DHCP server is unavailable • Provides a client with limited functionality on the network
Troubleshooting TCP/IP and Network Connectivity • TCP/IP comes with several command-line utilities that can be used to • Test network connectivity to make sure that computers can properly communicate over the network • Troubleshoot network connectivity problems
Verifying TCP/IP Configurations • ipconfig command • Can be used to verify the addressing parameters assigned to a host • Several parameters can be used with this command • winipcfg command • Used by Windows 9x machines to display the TCP/IP configuration settings • Very similar to the ipconfig utility used in Windows NT/2000/XP and Windows Server 2003
Verifying TCP/IP Configurations (Continued) • Information displayed using ipconfig or winipcfg can assist in determining whether the computer is using the correct • IP address • Subnet mask • Default gateway configuration
Verifying Network Connectivity • Windows Server 2003 provides a variety of TCP/IP utilities to troubleshoot connectivity problems • ping command • Tests network connectivity with other hosts on the network by sending ICMP packets to a remote computer and then listening for an echo reply from the remote host
Verifying Network Connectivity (Continued) • tracert command • Displays all the routers a packet must pass through in the journey to the remote host • Helps a network administrator better understand the true nature of a TCP/IP network communication issue
Verifying Network Connectivity (Continued) • pathping command • Combines the functions of both the ping and tracert commands • Sends echo request messages to each router between a source and destination host • Once complete, it • Computes results based on the packets returned from each router • Displays the degree of packet loss at each router • Can help a network administrator determine which routers are experiencing network problems or congestion
Verifying Network Connectivity (Continued) • route command • Used to view or modify the contents of a system’s local routing table
Verifying Network Connectivity (Continued) • netdiag command • Can be used to diagnose and troubleshoot a variety of network connectivity problems • Some of the information provided includes • A list of installed hotfixes • IP address and DNS settings • Domain configuration information
Administering DHCP in Windows Server 2003 • To implement automatic IP addressing for network systems • Install a DHCP service on at least one server on the network • Dynamic Host Configuration Protocol (DHCP) • Used to • Centralize the administration of IP addresses and other options • Eliminate the administrative overhead of statically assigning the information to each network host
Administering DHCP in Windows Server 2003 (Continued) • A DHCP scope • A range of IP addresses configured on a DHCP server that can be handed out to network clients • When a client is configured to use DHCP, it receives • An IP address • A subnet mask • Any other options that may have been configured for the scope
Administering DHCP in Windows Server 2003 (Continued) • A DHCP lease • An IP address that is assigned to a client from a DHCP server • A DHCP client attempts to lease an IP address in one of the following situations: • TCP/IP is installed and started for the first time • The client releases its IP address and attempts to renew another one • The client attempts to release a specific IP address and is denied
Installing a DHCP Server • The DHCP server must be assigned • A static IP address • A subnet mask • A default gateway (if required on the network)
Configuring DHCP Scopes • A DHCP scope • A range of IP addresses and associated settings that can be handed out to network clients configured to use automatic addressing • Configured using the DHCP MMC snap-in
Configuring DHCP Scopes (Continued) • Guidelines for creating a DHCP scope • Each DHCP scope should include only unique addresses to avoid duplicate IP addresses being handed out on the network • Any IP addresses that have been statically assigned to clients should be excluded from a scope to avoid duplication • DHCP servers can be configured with multiple scopes to assign IP addresses to hosts on different subnets
Configuring DHCP Scopes (Continued) • Scope options • Examples: default gateway, DNS server addresses • Must be configured before activating the scope • Client reservation • Reserves an IP address within the scope for a particular client so it is always reassigned the same address
Configuring DHCP Scopes (Continued) • Superscope • Grouping of scopes created for multiple subnets on a physical network • Usually created to make the administration of multiple scopes easier
Configuring DHCP Scopes (Continued) • Multicasting • Sending a message to a group of clients, but not all clients, using a single destination address • Uses a special range of IP addresses known as the Class D address range • DHCP servers in Windows Server 2003 can assign multicast addresses to clients as well as traditional unicast addresses
Authorizing a DHCP Server • Authorizing a DHCP server in Active Directory • The last step in installing a DHCP server • Designed to increase security and stability on a network • Only those Windows Server 2003 and Windows 2000 DHCP servers that have been authorized by an administrator are permitted to lease IP addresses
Using DHCP Options • Besides an IP address and a subnet mask, a range of DHCP options can be assigned to clients
Using DHCP Options (Continued) • Scope options can be configured at three levels • Server level • Server options apply to all scopes configured on the DHCP server • Scope level • Scope options only apply to a specific scope and the clients that lease an IP address from that scope • Client level • Client options apply to the specified client reservation
Configuring DHCP in a Routed Network • Options for implemented DHCP in a routed network • Install and configure a DHCP server on each subnet • Configure network routers to forward DHCP broadcast traffic
Configuring DHCP in a Routed Network (Continued) • Configure a DHCP relay agent on each of the subnets • The DHCP relay agent included with Windows Server 2003 • Relays DHCP broadcast messages between DHCP clients and DHCP servers across a routed network • Configured using the Routing and Remote Access tool
DHCP and DNS Integration • Dynamic DNS (DDNS) • Allows name servers and clients to automatically update the DNS database • Options for DNS registration • Dynamically update DNS A and PTR records only if requested by the DHCP clients • Selected by default • Always dynamically update DNS A and PTR records • Discard A and PTR records when lease is deleted • Dynamically update DNS A and PTR records for DHCP clients that do not request updates
Maintaining DHCP Services • Ways to monitor DHCP servers • Periodically look at the Event Viewer system log for any DHCP-related events • Use DHCP audit logging • Enabled by default in the DHCP MMC snap-in • Forces the DHCP server to place detailed event logs in the DHCP database directory
Summary (Continued) • TCP/IP consists of a suite of protocols that can be used to configure, manage, and troubleshoot network connectivity • The protocols include TCP, UDP, ARP, IP • All hosts on a TCP/IP network require an IP address and a subnet mask • A default gateway is needed to communicate outside of the local subnet • IP addresses can be assigned to a host • Statically • Dynamically by using a DHCP server
Summary (Continued) • Several utilities, such as ipconfig and ping, can be used to verify and troubleshoot TCP/IP • Once the DHCP service is installed, you must • Create and activate a unique scope • Authorize the DHCP server in Active Directory • You can also add various scope options, such as the IP address of the default gateway