Generation of dynamic DHCP snooping binding entries on S series switch

13

Information about generating DHCP snooping binding entries is as follows:

- When the dhcp snooping enable command is not run on the user-side interface and the network-side interface is not configured as a trusted interface, users can go online, but no DHCP snooping binding entry is generated.
- When the dhcp snooping enable command is not run on the user-side interface and the network-side interface is configured as a trusted interface, users can go online, but no DHCP snooping binding entry is generated.
- When the dhcp snooping enable command is run on the user-side interface and the network-side interface is not configured as a trusted interface, users cannot go online, but no DHCP snooping binding entry is generated.
- When the dhcp snooping disable command is run on the user-side interface, users can go online, but no DHCP snooping binding entry is generated no matter whether the network-side interface is configured as a trusted interface.
- When the dhcp snooping enable command is run on the user-side interface and both user-side and network-side interfaces are configured as trusted interfaces, users can go online, but no DHCP snooping binding entry is generated.
- If the DHCP snooping function has been enabled but no DHCP snooping entry is generated, you can check the device configuration in the preceding aspects.

Other related questions:
In which situation is a DHCP snooping binding entry generated
Information about generating DHCP snooping binding entries is as follows: 1. When the dhcp snooping enable command is not run on the user-side interface and the network-side interface is not configured as a trust interface, users can go online, but no DHCP snooping binding entry is generated. 2. When the dhcp snooping enable command is not run on the user-side interface and the network-side interface is configured as a trust interface, users can go online, but no DHCP snooping binding entry is generated. 3. When the dhcp snooping enable command is run on the user-side interface and the network-side interface is not configured as a trust interface, users cannot go online, but no DHCP snooping binding entry is generated. 4. When the dhcp snooping disable command is run on the user-side interface, users can go online, but no DHCP snooping binding entry is generated no matter whether the network-side interface is configured as a trust interface. 5. When the dhcp snooping enable command is run on the user-side interface and both user-side and network-side interfaces are configured as trust interfaces, users can go online, but no DHCP snooping binding entry is generated. If the DHCP snooping function has been enabled but no DHCP snooping entry is generated, you can check device configuration in the preceding aspects.

Static DHCP binding entries supported by S series switches
S series switches excluding the S1700 support static DHCP binding. Ensure that IP addresses exist in the address pool during static binding. In addition, to learn the maximum number of entries, you can contact Huawei technical support personnel.

Automatic backup of DHCP snooping binding table on S series switch
For S series switches in V200R003C00 and later versions, you can run the dhcp snooping user-bind autosave file-name [ write-delay delay-time ] command to enable automatic backup of the DHCP snooping binding table and specify the backup interval. By default, local automatic backup of the DHCP snooping binding table is disabled. By default, S series modular switches and fixed switches back up the DHCP snooping binding table every 1 hour and every 24 hours, respectively.

Reasons why IP packets matching binding entries are discarded a while after S series switch generates the dynamic binding table
After the dynamic binding table on the S series switches is generated for a while, If the IP packets that match the entries in the binding table are discarded, you need to check that the binding table still exists. The dynamic binding table has the aging time. If the IP address lease is not renewed after the aging time expires, the binding table ages out. As a result, the IP packets that match entries in the expired binding table are discarded.

Number of supported static DHCP binding entries on S series switch
S series switches (except S1700 switches) support the static DHCP binding configuration. When configuring static DHCP binding, ensure that IP addresses to be bound exist in a DHCP address pool. If you want to know the maximum number of static DHCP binding entries that can be configured, send an email to e_online@huawei.com.

If you have more questions, you can seek help from following ways:
To iKnow To Live Chat
Scroll to top