The user-bind command is used to create a static DHCP binding table. The dynamic DHCP binding table is automatically generated after DHCP snooping is enabled.
        In V100R002, the dhcp snooping check user-bind enable command is used to filter packets. After the function of checking DHCP messages against the binding table is enabled, the packets entering a device match binding entries. The matching packets pass through and the packets that do not match entries are discarded. If the dhcp snooping check user-bind enable command is not used, packet filtering takes no effect. In V100R003 and later versions, the ip source check user-bind enable command is used to filter packets.

In the interface view:

•  Interface and IP address
•  Interface and MAC address
•  Interface, IP address, and MAC address
•  Interface, IP address, and VLAN ID
•  Interface, MAC address, and VLAN ID
•  Interface, IP address, MAC address, and VLAN ID

In the VLAN view:

•  VLAN ID and IP address
•  VLAN ID and MAC address
•  VLAN ID, IP address, and MAC address
•  VLAN ID, IP address, and interface
•  VLAN ID, MAC address, and interface
•  VLAN ID, IP address, MAC address, and interface 

        For example, VLAN ID and IP address indicates that the packets whose IP address and VLAN matching the binding entry are allowed to pass through, regardless of the interface receiving the packets and the MAC address of the packets.