Technical Documentation

Automatically Logging Out DHCP Clients

You can configure the extended DHCP local server and extended DHCP relay to automatically log out DHCP clients. Auto logout immediately releases an existing client when DHCP receives a discover packet that has the same DHCP option 60 and DHCP option 82 information as the existing client. DHCP then releases the existing client IP address without waiting for the normal lease expiration.

Note: When the existing client is released, the new client undergoes the normal authentication process. The new client might not receive the same IP address as the original client.

To configure DHCP client auto logout:

  1. Specify that you want to configure override options.
    • For DHCP local server:
      [edit system services dhcp-local-server]user@host# edit overrides
    • For DHCP relay agent:
      [edit forwarding-options dhcp-relay]user@host# edit overrides
  2. Enable auto logout. (DHCP local server and DHCP relay agent both support the client-discover-match statement.)

Note: If you change the auto logout configuration, existing clients continue to use the auto logout setting that was configured when they logged in. New clients use the new setting.


Published: 2010-04-15