1. Chapter 8
Administering TCP/IP

2. 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

3. 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

4. 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

5. Four layers of the TCP/IP model

6. 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

7. 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

8. 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

9. 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:
A subnet mask
Used to determine which portion of an address represents the network and which portion represents a unique host on that network

10. 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

11. 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

12. 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

13. Manually Configuring TCP/IP Properties

14. TCP/IP Options

15. 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

16. 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

17. Configuring TCP/IP properties dynamically using DHCP

18. 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

19. 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

20. Ipconfig parameters

21. 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

22. 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

23. Ping parameters

24. 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

25. 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

26. Pathping parameters

27. Verifying Network Connectivity (Continued)
route command
Used to view or modify the contents of a system’s local routing table

28. 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

29. 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

30. 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

31. 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

32. 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)

33. 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

34. The DHCP MMC snap-in

35. 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

36. 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

37. 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

38. 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

39. 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

40. Using DHCP Options
Besides an IP address and a subnet mask, a range of DHCP options can be assigned to clients

41. 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

42. 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

43. 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

44. Routing and Remote Access console

45. 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

46. DHCP and DNS integration properties

47. 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

48. DHCP service activity log

49. 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

50. 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

51. Summary (Continued)
Windows 2000 and XP DHCP clients automatically update resource records with the DNS server
The DHCP server can be configured to perform all updates and perform updates on behalf of legacy clients