Configuring an Interface as the Trusted Interface
Context
To enable DHCP clients to obtain IP addresses from authorized DHCP servers, configure the interfaces directly or indirectly connected to the DHCP servers trusted by the administrator as the trusted interfaces, and other interfaces as untrusted interfaces. This prevents bogus DHCP servers from assigning IP addresses to DHCP clients.
After enabling DHCP snooping on the interface (including Layer 2 subinterfaces) or in the VLAN connected to the user, configure the interface connected to the DHCP server as the trusted interface, so that the dynamic DHCP snooping binding table is generated.
Procedure
- Run system-view
The system view is displayed.
- Configure the interface as the trusted interface in the interface view or VLAN view.
In the interface view:
In the VLAN view:
- Run dhcp snooping trusted interface interface-type interface-number
The interface is configured as the trusted interface.
By default, an interface is an untrusted interface.
If you run this command in the VLAN view, the command takes effect only on DHCP messages in this VLAN received from interfaces that belong to this VLAN. If you run the dhcp snooping trusted command in the interface view, the command takes effect for all the DHCP messages received on the specified interface.
- Run commit
The configuration is committed.
