Troubleshooting the DHCP Relay Agent

  • Article

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Troubleshooting the DHCP Relay Agent

What problem are you having?

  • The DHCP Relay Agent is not providing relay services for DHCP clients on a network segment.
The DHCP Relay Agent is not providing relay services for DHCP clients on a network segment.

Cause:  The interface on the server running Routing and Remote Access that connects to the network segment where the DHCP clients are located is not added to the DHCP Relay Agent IP routing protocol.

Solution:  Verify that the interface on the server running Routing and Remote Access that connects to the network segment where the DHCP clients are located is added to the DHCP Relay Agent IP routing protocol.

See also:  Enable the DHCP Relay Agent on a router interface

Cause:  The Relay DHCP packets check box is not selected for the DHCP Relay Agent interface that is connected to the network segment where the DHCP clients are located.

Solution:  Verify that the Relay DHCP packets check box is selected for the DHCP Relay Agent interface that is connected to the network segment where the DHCP clients are located.

Cause:  The IP addresses of DHCP servers configured on the global properties of the DHCP Relay Agent are incorrect.

Solution:  Verify that the IP addresses of DHCP servers configured on the global properties of the DHCP Relay Agent are the correct IP addresses for DHCP servers on your internetwork.

See also:  Configure global DHCP Relay Agent properties

Cause:  The correctly configured DHCP servers are not reachable.

Solution:  From the router with the DHCP Relay Agent enabled, use the ping command to ping each of the DHCP servers that are configured in the global DHCP Relay Agent dialog box. If you cannot ping the DHCP servers from the DHCP Relay Agent router, troubleshoot the lack of connectivity between the DHCP Relay Agent router and the DHCP server or servers.

See also:  Troubleshooting TCP/IP

Cause:  IP packet filtering is preventing the receiving (through input filters) or sending (through output filters) of DHCP traffic.

Solution:  Verify that IP packet filtering on the router interfaces is not preventing the receiving (through input filters) or sending (through output filters) of DHCP traffic. DHCP traffic uses the User Datagram Protocol (UDP) ports of 67 and 68.

See also:  Manage Packet Filters

Cause:  TCP/IP filtering is preventing the receiving of DHCP traffic.

Solution:  Verify that TCP/IP filtering on the router interfaces is not preventing the receiving of DHCP traffic. DHCP traffic uses the UDP ports of 67 and 68.

See also:  Configure TCP/IP to use TCP/IP filtering