Clearing DHCP snooping table overview

Commands are available to dynamically learn DHCPv4 snooping bindings and clear DHCP snooping tables dynamic binding table entries.

These commands will:

  • Allow the administrator to clear all entries in DHCP snooping binding tables.

  • Allow the administrator to selectively clear DHCP snooping bindings by filtering entries by IP, VLAN, or port number.


  • When a dynamically learned binding is cleared, DHCPv4 snooping drops any further DHCP messages (DHCP REQUEST , DHCP INFORM and DHCP RELEASE) from that client.

  • Clearing of a dynamically learned DHCPv4 snooping binding would not be synced to the DHCP server and the DHCP client.

    The administrator will receive a warning about these limitations before proceeding with the clear command execution.

    Execution of this command results in clearing of dynamically learnt DHCP Snooping entries from the binding table on this switch. Since the DHCP Server and the DHCP Clients would not be aware of this change, this can have side effects.

  • The client will not be allowed to renew the IP address until the client sends a new DHCP DISCOVER packet. This process will allow the IP access to renew through to the server.

  • The DHCP Server will consider the IP as assigned for the entire duration of the lease time even if the client attempts to release or renew the IP.

  • If Dynamic IP Lockdown is enabled, the clearing of a dynamic DHCP snooping table binding will result in removal of the Dynamic IP Lockdown entry for that client. This action results in data packets being dropped until a new DHCP snooping table binding is added.

  • If Dynamic Address Resolution Protocol Protection (DARPP) is enabled, clearing of a dynamic DHCP snooping table binding results in ARP packets being dropped from the client by DARPP until a new DHCP snooping table binding is added.

One or more dynamic bindings from DHCP snooping binding table may have to be removed in following cases:

  • Change of the DHCPv4 Server.

  • Change to the configuration of the server.

  • Changes in the network topology causing clients to be moved to a different VLAN or port.

  • Clearing existing binding entries of inactive clients.


Clearing DHCP snooping table is not available in these circumstances:

  • Support is unavailable for clearing static bindings.

  • Support is unavailable for DHCPv6 snooping.