When a DHCP server is unavailable on a Windows Vista-based computer, Windows Vista uses an APIPA IP address much sooner than Windows XP does under the same circumstances

When a DHCP server is unavailable on a Windows Vista-based computer, Windows Vista uses an APIPA IP address much sooner than Windows XP does under the same circumstances: "This behavior occurs if Windows Vista cannot immediately contact a DHCP server. In this situation, Windows Vista tries for only six seconds to contact a DHCP server and then uses an APIPA IP address. Then, Windows Vista continues trying to acquire an IP address from a DHCP server."