How do i configure DHCP for automatic discovery of ISA Server?
Click Start, point to Programs, point to Administrative Tools, and then click DHCP.
In the console tree, right-click the applicable DHCP server, click Set Predefined Options, then click Add.
Click Add. In Name, type WPAD. In Code, type 252.
In Data type, select String and then click OK.
In String, type: http://Computer_Name:AutoDiscoveryPortNumber/Wpad.dat
Where Computer_Name is the fully qualified domain name of the ISA Server computer or array and AutoDiscoveryPortNumber is the port number on which auto-discovery information is published. This port is either the outgoing Web request port number or an additional port used for automatic discovery publishing.
Right-click Server options and then click Configure options. Verify that Option 252 check box is selected.