1. Module 4: Planning, Optimizing, and Troubleshooting DHCP

2. Overview Planning a DHCP Strategy Securing a DHCP Solution
Optimizing DHCP
Troubleshooting DHCP

3. Lesson: Planning a DHCP Strategy
Multimedia: Planning DHCP Server Placement in the Enterprise
Best Practices for Determining DHCP Server Placement
Choosing a DHCP Infrastructure
Defining Scope Reservations
Selecting DHCP Options
Selecting Option Classes
Guidelines for Planning a DHCP Strategy

4. Multimedia: Planning DHCP Server Placement in the Enterprise
The objective of this presentation is to plan the placement of DHCP servers in a Windows Server 2003 enterprise network
You will learn how to:
Explain the considerations for a single or multiple DHCP server plan
Determine when to use a single or multiple DHCP server solution to meet organizational requirements

5. Best Practices for Determining DHCP Server Placement
Description
Place DHCP servers to minimize traffic across low-speed links
Place servers locally when you have a site that is across a slow link to minimize low-speed traffic
Place DHCP servers to optimize response times
Place DHCP servers to optimize response times for all clients on the LAN
Configure at least one backup server for fault tolerance
You can configure another server by using the 80/20 rule for scopes, configure a DHCP cluster, or use a standby server
Place DHCP server in a screened subnet
Place DHCP servers to provide services for a Web farm
Place DHCP servers close to population
Place DHCP servers on subnets with the highest client population or high lease renewals
Test server placement first in a lab
By testing server placement, you will validate your chosen plan

6. Choosing a DHCP Infrastructure
LAN 1
LAN 2
DHCP server
DHCP server
Remote LAN 3
Determining the type of DHCP infrastructure to be used
Centralized
Distributed
Mixed infrastructure
DHCP server

7. Defining Scope Reservations
Create a scope reservation when:
The device always requires the same address
Multiple DHCP servers service the reserved client
The client has a previously assigned IP address
More than one DHCP server can be reached by a reserved client

8. Selecting DHCP Options
Description
Routers
A preferred list of IP addresses for routers on the same subnet as the DHCP clients
DNS servers
IP addresses for DNS name servers that DHCP clients use to resolve names
DNS domain
Domain name that DHCP clients should use when resolving names
WINS node type
A preferred NetBIOS name resolution method for the DHCP client to use
WINS server
IP addresses of primary and secondary WINS servers for the DHCP client to use

9. Selecting Option Classes
Vendor-defined classes manage DHCP options identified by operating system vendor type
User-defined classes manage DHCP options with common configuration requirements
Windows 98 Client 1
Client 2
Vendor class configuration A
Vendor class configuration B
Vendor class configuration C
Client 3
DHCP Server

10. Guidelines for Planning a DHCP Strategy
Evaluate the network topology
Determine which DHCP infrastructure you will use
Determine reservations
Define DHCP options
Determine integration issues
Determine the fault tolerance approach

11. Practice: Identifying DHCP Planning Issues
In this practice, you will determine a network configuration that meets the needs of the scenario

12. Lesson: Securing a DHCP Solution
Securing the DHCP Service
Preventing Unauthorized DHCP Servers
Securing DHCP in Screened Subnets

13. Securing the DHCP Service
Active Directory
Authorized List
DHCP Server 1
DHCP Server 2
DHCP Administrators
DHCP Server 1
DHCP Server 2
DHCP Log
DHCP Users

14. Preventing Unauthorized DHCP Servers
Active Directory
DHCP Service
Using DHCP servers in Windows 2000
Authorizing DHCP servers in Active Directory
DHCPINFORM
DHCP Server Object
Authorized List
In authorized list
(Startup)
Not in authorized list
(Shut down)
Authorized Windows Server 2003 DHCP Server
Unauthorized Windows Server 2003 DHCP Server

15. Securing DHCP in Screened Subnets
Internet
External Firewall
Internal Firewall
DHCP Server
Private Network
Screened Subnet
Shared Resource Server
Web and Shared Resource Server

16. Practice: Identifying Authorization Issues
In this practice, you will identify why clients are unable to access network resources.

17. Lesson: Optimizing DHCP
Improving the DHCP Server
Modifying Lease Duration

18. Improving the DHCP Server
Factors that impact DHCP server performance include:
The speed of server disk drives.
The amount of RAM available on the DHCP server computer.

19. Modifying Lease Duration
Option
When to use
Result
Increase the lease duration
At least 20 percent of IP addresses in scope is available
Configurations that rarely change on the network
Can reduce DHCP–related network traffic
Reduce the lease duration
Limited number of IP addresses available
Client configurations change
Clients move often on your network
Remote access clients
Reduce the chance of running out of addresses to lease

20. Practice: Modifying Lease Duration to Improve DHCP Performance
In this practice, you will modify lease duration to improve DHCP performance

21. Lesson: Troubleshooting DHCP
Defining DHCP Problems
DHCP Troubleshooting Tools
Troubleshooting Common DHCP Issues
How to Troubleshoot DHCP Issues

22. Defining DHCP Problems
Is service operating properly?
Are scopes configured correctly?
Are leases available for proper scopes?
Is the client properly connected to the network?
Are you getting a lease?
Where is the lease originating?
Are relay agents and routers configured properly?
Are packets routing between subnets?
How many clients are affected?
Significant number of clients affected
Only one client affected
Server-side issue
Client-side issue
Infrastructure issue

23. DHCP Troubleshooting Tools
Purpose
Network Monitor
For viewing packet-level information
DHCP Audit Log
Log DHCP events and critical errors
IPconfig
For generating DHCP traffic for testing purposes and reviewing current configuration

24. Troubleshooting Common DHCP Issues
Client-side problems
Server-side problems
Relay agent problems
DHCP database problems

25. How to Troubleshoot DHCP Issues
In this procedure, you will learn how to troubleshoot DHCP issues

26. Practice: Troubleshooting DHCP Issues
In this practice, you will determine DHCP troubleshooting steps

27. Lab A: Planning a DHCP Strategy
Exercise 1: Planning the DHCP Solution

28. Lab B: Troubleshooting DHCP Issues
Exercise 1: Optimizing DHCP Redundancy for Multiple Subnets
Exercise 2: Troubleshooting DHCP Problems