Third-party DHCP server may assign duplicate IP addresses to clients that are behind a network bridge

Your Dynamic Host Control Protocol (DHCP) client computer is located behind a Microsoft Windows XP-based host computer and has a network bridge configured. Your DHCP client computer tries to obtain an IP address from a third-party DHCP server. You receive a "duplicate IP address" error message. This issue may occur in network environments where a DSL modem, router, or switch acts as a DHCP server.

Note A Windows XP-based host computer is a computer that runs Windows XP and that shares its network connection with other computers.

This issue can occur if the third-party DHCP server incorrectly uses the MAC address from the CHADDR (the Client hardware address) field of the DHCP Request packet (instead of the Client Identifier field) to identify the client that is requesting a DHCP lease. Request for Comments (RFC) 2131 states that the DHCP server must use the Client Identifier field (if used by the client) to identify the client.

To resolve this issue, contact the manufacturer of the DHCP server to inquire about the availability of a fix for this issue.