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Oracle Solaris Administration: IP Services     Oracle Solaris 10 1/13 Information Library
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Document Information


Part I Introducing System Administration: IP Services

1.  Oracle Solaris TCP/IP Protocol Suite (Overview)

Part II TCP/IP Administration

2.  Planning Your TCP/IP Network (Tasks)

3.  Introducing IPv6 (Overview)

4.  Planning an IPv6 Network (Tasks)

5.  Configuring TCP/IP Network Services and IPv4 Addressing (Tasks)

6.  Administering Network Interfaces (Tasks)

7.  Configuring an IPv6 Network (Tasks)

8.  Administering a TCP/IP Network (Tasks)

9.  Troubleshooting Network Problems (Tasks)

10.  TCP/IP and IPv4 in Depth (Reference)

11.  IPv6 in Depth (Reference)


12.  About DHCP (Overview)

13.  Planning for DHCP Service (Tasks)

Preparing Your Network for the DHCP Service (Task Map)

Mapping Your Network Topology

Network Topology to Avoid

Determining the Number of DHCP Servers

Updating System Files and Netmask Tables

Making Decisions for Your DHCP Server Configuration (Task Map)

Selecting a Host to Run the DHCP Service

Choosing the DHCP Data Store

Setting a Lease Policy

Determining Routers for DHCP Clients

Making Decisions for IP Address Management (Task Map)

Number and Ranges of IP Addresses

Client Host Name Generation

Default Client Configuration Macros

Dynamic and Permanent Lease Types

Reserved IP Addresses and Lease Type

Planning for Multiple DHCP Servers

Planning DHCP Configuration of Your Remote Networks

Selecting the Tool for Configuring DHCP

DHCP Manager Features

dhcpconfig Features

Comparison of DHCP Manager and dhcpconfig

14.  Configuring the DHCP Service (Tasks)

15.  Administering DHCP (Tasks)

16.  Configuring and Administering the DHCP Client

17.  Troubleshooting DHCP (Reference)

18.  DHCP Commands and Files (Reference)

Part IV IP Security

19.  IP Security Architecture (Overview)

20.  Configuring IPsec (Tasks)

21.  IP Security Architecture (Reference)

22.  Internet Key Exchange (Overview)

23.  Configuring IKE (Tasks)

24.  Internet Key Exchange (Reference)

25.  IP Filter in Oracle Solaris (Overview)

26.  IP Filter (Tasks)


27.  Introducing IPMP (Overview)

28.  Administering IPMP (Tasks)

Part VI IP Quality of Service (IPQoS)

29.  Introducing IPQoS (Overview)

30.  Planning for an IPQoS-Enabled Network (Tasks)

31.  Creating the IPQoS Configuration File (Tasks)

32.  Starting and Maintaining IPQoS (Tasks)

33.  Using Flow Accounting and Statistics Gathering (Tasks)

34.  IPQoS in Detail (Reference)



Preparing Your Network for the DHCP Service (Task Map)

Before you set up your network to use DHCP, you must collect information to help you make decisions for configuring one or more servers. Use the task map in the following table to identify the tasks for preparing your network for DHCP. The table lists the tasks, descriptions of what each task accomplishes, and the sections that detail the steps to perform the individual tasks.

For Instructions
Map your network topology.
Determine and locate the services that are available on the network.
Determine the number of DHCP servers you need.
Use the expected number of DHCP clients as a basis for determining the number of DHCP servers you need.
Update system files and netmasks table.
Reflect the network topology accurately.

Mapping Your Network Topology

If you have not already done so, you should map the physical structure of your network. Indicate the location of routers and clients, and the location of servers that provide network services. This map of your network topology can help you determine which server to use for the DHCP service. The map can also help you determine the configuration information that the DHCP server can provide to clients.

See Chapter 2, Planning Your TCP/IP Network (Tasks) for more information about planning your network.

The DHCP configuration process can gather some network information from the server's system and network files. Updating System Files and Netmask Tables discusses these files. However, you might want to give clients other service information, which you must enter into the server's macros. As you examine your network topology, record the IP addresses of any servers you want your clients to know about. The following servers, for example, might provide services on your network. The DHCP configuration does not discover these servers.

Network Topology to Avoid

In some IP network environments, several local area networks (LANs) share the same network hardware media. The networks may use multiple network hardware interfaces or multiple logical interfaces. DHCP does not work well in this kind of shared media network. When multiple LANs run across the same physical network, a DHCP client's request arrives on all network hardware interfaces. This effect makes the client appear to be attached to all of the IP networks simultaneously.

DHCP must be able to determine the address of a client's network in order to assign an appropriate IP address to the client. If more than one network is present on the hardware media, the server cannot determine the client's network. The server cannot assign an IP address without knowing the network number.

You can use DHCP on only one of the networks. If one network does not suit your DHCP needs, you must reconfigure the networks. You should consider the following suggestions:

Determining the Number of DHCP Servers

The data store option that you choose has a direct effect on the number of servers you must have to support your DHCP clients. The following table shows the maximum number of DHCP and BOOTP clients that can be supported by one DHCP server for each data store.

Table 13-1 Estimated Maximum Number of Clients Supported by One DHCP Server

Data Store Type
Maximum Number of Clients Supported
Text files
Binary files

This maximum number is a general guideline, not an absolute number. A DHCP server's client capacity depends greatly on the number of transactions per second that the server must process. Lease times and usage patterns have a significant impact on the transaction rate. For example, suppose leases are set to 12 hours and users turn their systems off at night. If many users turn on their systems at the same time in the morning, the server must handle transaction peaks as many clients request leases simultaneously. The DHCP server can support fewer clients in such an environment. The DHCP server can support more clients in an environment with longer leases, or an environment that consists of constantly connected devices such as cable modems.

The section Choosing the DHCP Data Store compares the types of data stores.

Updating System Files and Netmask Tables

During DHCP configuration, the DHCP tools scan various system files on your server for information that can be used to configure the server.

You must be sure the information in the system files is current before you run DHCP Manager or dhcpconfig to configure your server. If you notice errors after you configure the server, use DHCP Manager or dhtadm to modify the macros on the server.

The following table lists some of the information gathered during DHCP server configuration, and the sources for the information. Be sure this information is set correctly on the server before you configure DHCP on the server. If you make changes to the system files after you configure the server, you should reconfigure the service to reflect these changes.

Table 13-2 Information Used for DHCP Configuration

Time zone
System date, time zone settings
The date and time zone are initially set during Oracle Solaris installation. You can change the date by using the date command. You can change the time zone by changing the timezone/localtime property in the svc:/system/environment:init SMF service to set the TZ environment variable. See the TIMEZONE(4) man page for more information.
DNS parameters
The DHCP server uses the /etc/resolv.conf file to obtain DNS parameters such as the DNS domain name and DNS server addresses. See System Administration Guide: Naming and Directory Services (DNS, NIS, and LDAP) or the resolv.conf(4) man page for more information about resolv.conf.
NIS or NIS+ parameters
System domain name, nsswitch.conf, NIS or NIS+
The DHCP server uses the domainname command to obtain the domain name of the server system. The nsswitch.conf file tells the server where to look for domain-based information. If the server system is an NIS or NIS+ client, the DHCP server performs a query to get NIS or NIS+ server IP addresses. See the nsswitch.conf(4) man page for more information.
Default router
System routing tables, user prompt
The DHCP server searches the network routing tables to find the default router for clients that are attached to the local network. For clients not on the same network, the DHCP server must prompt you for the information.
Subnet mask
Network interface, netmasks table
The DHCP server looks to its own network interfaces to determine the netmask and broadcast address for local clients. If the request was forwarded by a relay agent, the server obtains the subnet mask in the netmasks table on the relay agent's network.
Broadcast address
Network interface, netmasks table
For the local network, the DHCP server obtains the broadcast address by querying the network interface. For remote networks, the server uses the BOOTP relay agent's IP address and the remote network's netmask to calculate the broadcast address for the network.