DHCP OPTIONS NOT UPDATED ON LEASE RENEWAL

The most convenient method of distributing IP addresses to Windows 9x clients on a LAN is to operate a Dynamic Host Configuration Protocol (DHCP) network server. In fact, Microsoft Windows NT and 2000 Server both include DHCP server software. Having this installed allows a number of setting Options for DHCP scope, such as Default Gateway, Node Type, and WINS Server addresses. The option values are sent to the Windows clients when an IP address lease is obtained.

Windows 9x clients will attempt to renew the lease part way through the lease period. This enables it to keep its current IP address. But if the network administrator changes the values of DHCP Options on the DHCP server (for example, the administrator changes the IP address of the Default Gateway), the Windows 9x client will not update some of these Option values in its IP configuration during the lease renewal.

To force important Option value changes to take effect, it is necessary to manually release and then renew the DHCP lease. You can do this using the Winipcfg.exe program, which allows you to select a network card and gives you a Release and Renew button.

In short, Microsoft gives this summary:

CHANGES MADE ON LEASE RENEWAL (DOES NOT NEED A MANUAL RELEASE AND RENEW)

DNS server

CHANGES MADE ON RELEASE AND RENEWAL

DNS domain name

WINS server

Router options (where the Default Gateway would be set)

CHANGES MADE ON RESTART OF COMPUTER

Node type

Scope ID (legacy option not frequently used)