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Event ID 1002 — DHCP Client Address Conflicts

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Applies To: Windows Server 2008 R2

Dynamic Host Configuration Protocol (DHCP) operates on a lease renewal basis. During the leasing process, IP address conflicts can occur as leases are renewed and expired. Client lease requests might be denied by the server for invalid (out of pool) or duplicate IP addresses. Multiple IP address conflict messages can indicate that your lease period, your scope, or both, need adjustment in your DHCP server configuration.

Event Details

Product: Windows Operating System
ID: 1002
Source: Microsoft-Windows-DHCP-Client
Version: 6.1
Symbolic Name: EVENT_NACK_LEASE
Message: The IP address lease %1 for the network adapter with MAC address %2 has been denied by the DHCP server %3 (The DHCP server sent a DHCPNACK message).

Resolve

Renew the client DHCP lease

The IP address for this computer is the same IP address used by another computer on the network. No user action is required. The DHCP client will attempt to get a new IP address from the DHCP server.

To perform these procedures, you must be a member of the Administrators group, or you must have been delegated the appropriate authority.

If you do not want to wait for the client to make its automatic renewal attempt, you can manually release and renew the IP address of the client by following these steps:

  1. At the DHCP-enabled client computer, click Start, in Start Search type cmd, and then press ENTER.
  2. Type ipconfig /release, and then press ENTER.
  3. Type ipconfig /renew, and then press ENTER.

Verify

To verify that address conflicts have been resolved:

  1. At the DHCP-enabled client computer, click Start, in Start Search type cmd, and then press ENTER.
  2. To verify a DHCP client lease, type ipconfig /all to view lease-status information.
  3. The output of the ipconfig command should show an IPv4 or IPv6 address marked "preferred."

DHCP Client Address Conflicts

DHCP Infrastructure