Consider the following scenario:
In this scenario, an Error event that resembles one of the following Event ID 20291 events is logged under the "Applications and Services Logs/Microsoft/Windows/Microsoft-Windows-DHCP Server Events" path in Event Viewer:
- You have two DHCP servers that are running Windows Server 2012 R2.
- You configure the servers as a failover cluster.
- You set up multiple DHCP scopes and multiple IP networks.
- You put a client computer on one of the IP networks and confirm that it receives an IP address from one of the scopes.
- You move the client computer to a different IP network.
In this scenario, an Error event that resembles one of the following Event ID 20291 events is logged under the "Applications and Services Logs/Microsoft/Windows/Microsoft-Windows-DHCP Server Events" path in Event Viewer:
Source: Microsoft-Windows-DHCP-Server
Date: date/time
Event ID: 20291
Task Category: DHCP Failover
Level: Error
User: NETWORK SERVICE
Computer: DHCP-NODE
Description: A BINDING-ACK message with transaction id: number was sent for IP address: address with reject reason: (Fatal conflict exists: address in use by other client) to partner server: other_dhcp_node for failover relationship: failover_name.
Date: date/time
Event ID: 20291
Task Category: DHCP Failover
Level: Error
User: NETWORK SERVICE
Computer: DHCP-NODE
Description: A BINDING-ACK message with transaction id: number was sent for IP address: address with reject reason: (Fatal conflict exists: address in use by other client) to partner server: other_dhcp_node for failover relationship: failover_name.
Source: Microsoft-Windows-DHCP-Server
Date: date/time
Event ID: 20291
Task Category: DHCP Failover
Level: Error
User: NETWORK SERVICE
Computer: DHCP-NODE
Description: A BINDING-ACK message with transaction id: Transaction_Number was sent for IP address: IP_Address with reject reason: (Reject Reason Unknown) to partner server: DHCP_Partner_Server for failover relationship: DHCP_Failover_Relationship_Name.
Date: date/time
Event ID: 20291
Task Category: DHCP Failover
Level: Error
User: NETWORK SERVICE
Computer: DHCP-NODE
Description: A BINDING-ACK message with transaction id: Transaction_Number was sent for IP address: IP_Address with reject reason: (Reject Reason Unknown) to partner server: DHCP_Partner_Server for failover relationship: DHCP_Failover_Relationship_Name.