Contents
 DHCP Controller

DHCP Controller is a client program that works in conjunction with a DHCP Server to automatically configure your PC for network operation.

Note: The DHCP Controller application is not available unless you specify the use of DHCP in the TCP/IP portion of the Configuration program.

Introduction

What the DHCP Controller Can Do

How To...

View Your PC's IP Address and Lease Expiration Time

Extend an IP Address Lease

Release an IP Address Lease

Specify Advanced  DHCP Settings


What the DHCP Controller Can Do

If you enable DHCP when you configure your TCP/IP settings, your PC will request configuration information from a DHCP server each time you start Windows. Your system administrator determines the configuration information supplied by the DHCP server to your PC. In addition to an IP address, the DHCP server usually provides your PC with name service information, authentication information, routing information, a broadcast address, a subnet mask, and other configuration details.

In addition, DHCP configuration can apply to more than one network interface. For example, if you've configured your PC to use an Ethernet and a serial interface, DHCP can configure your Ethernet interface (pk0, nd1, etc.) and your serial network interface (pp0). An option in the DHCP Controller dialog allows you to specify interfaces.

You can use the DHCP Controller to extend the lease of the IP address or to release the address lease assigned to a particular interface. When you extend a lease, you retain your PC's present IP address until the time specified. When you release a lease, you are disconnected from the network, and the IP address assigned to your PC is returned to the IP address pool. You can extend a lease by the amount of time already used by the lease. For example, 25 days into a 60-day lease, you can extend the lease for 25 additional days.

Settings supplied by DHCP take precedence over locally specified settings. For example, if you change a DHCP-supplied configuration setting such as the time zone, the DHCP server will reset this setting the next time you start Windows.

Tip: Release an IP address lease when you take a PC out of service or move it to another subnetwork. If you do not release the lease, the IP address assigned to the PC remains unavailable until the lease expires.


How to View Your PC's IP Address and Lease Expiration Time

1.	Double-click the DHCP Controller icon.

The DHCP Controller dialog opens.

2.	Click the interface whose IP address you want to view.

The interface is highlighted.

3.	Note the IP address and Lease Expiration values for this interface appearing in the dialog.

DHCP values displayed are your PC's present DHCP assignment for this interface.

Note: Due to the nature of a PPP connection, the IP address assigned to a PPP interface can change during a PPP session.

See Also:

How to Extend an IP Address Lease

How to Release an IP Address Lease


How to Extend an IP Address Lease

1.	Double-click the DHCP Controller icon.

The DHCP Controller dialog box opens.

2.	Click the interface whose IP address lease you want to extend.

The interface is highlighted.

3.	Select a time unit by clicking an option button in the Lease Extension panel.

For example, to increase the lease for a number of days, click the Days option button.

4.	Enter a value in the Lease Extension edit box.

For example, to extend the lease for 10 days, enter 10 in the edit box.

5.	Choose Extend.

The DHCP Controller relays your request to the DHCP server. If the server approves your request, the Lease Expiration field is updated to reflect the lease extension. If the DHCP server denies your request, a message box informs you that your lease cannot be extended.

Note: You can extend a lease by the amount of time already used by the lease. For example, 25 days into a 60-day lease, you can extend the lease for 25 additional days.

See Also:

How to Release an IP Address Lease


How to Release an IP Address Lease

1.	Double-click the DHCP Controller icon.

The DHCP Controller dialog box opens.

2.	Click the interface whose IP address you want to release.

The interface is highlighted.

3.	Choose Release.

A dialog box opens, asking you if you really want to release the lease and disconnect from the network.

4.	Choose Yes to release the lease and disconnect from the network.

Alternatively, choose Cancel to retain the lease and network connection.

See Also:

How to Extend an IP Address Lease


Specifying Advanced PPP Settings

There are three additional DHCP settings you can specify:

Alternate Client Identifier - An alternate DHCP client identifier, such as a serial number, property number, or DNS domain.

Alternate Client Class - An alternate or administrator-defined client class identifier.

Maximum DHCP Attempts - The number of attempts the DHCP client makes before determining that the DHCP server is unavailable.

You access these settings from the Advanced Settings menu in the Configuration program. Refer to Configuration help for more information about these settings.


DHCP

The Dynamic Host Configuration Protocol (DHCP) lets a PC retrieve the parameters required to operate in a network environment, such as an IP address, from a server.


DHCP Server

A DHCP Server responds to configuration requests from DHCP client programs and manages the allocation of client IP addresses and leases.

A DHCP Server is supplied with most operating system software, including SunOS 5.3. More than one DHCP server can be connected to the network. When only one server is in use, a relay agent can be used to relay DHCP configuration requests from a subnet without a DHCP server to a subnet with a DHCP server.

Refer to the documentation supplied with your operating system for specific information about configuring and using your DHCP server software.


Lease

A lease represents the time period for which an IP address assigned by DHCP is valid. The lease expiration date and time are displayed in the Dynamic Host Configuration Tool dialog. You can extend a lease, providing that the DHCP server from which you obtained the lease approves your request for extension. You can release a lease at any time. When you release a lease, you disconnect from the network.


IP Address

A four-part number that uniquely identifies every computer connected to a TCP/IP network.