Siemens S323 User Manual

UMN:CLI                                                                                                                                                              User  Manual 

SURPASS hiD 6615 S223/S323 R1.5 

258                                                                         A50010-Y3-C150-2-7619 

For enhanced security, the hiD 6615 S223/S323 provides the DHCP snooping feature. 
The DHCP snooping filters untrusted DHCP messages and maintains a DHCP snooping 
binding table. An untrusted message is a message received from outside the network, 
and an untrusted interface is an interface configured to receive DHCP messages from 
outside the network. 

The DHCP snooping basically permits all the trusted messages received from within the 
network and filters untrusted messages. In case of untrusted messages, all the binding 
entries are recorded in a DHCP snooping binding table. This table contains a hardware 
address, IP address, lease time, VLAN ID, interface, etc. 

It also gives you a way to differentiate between untrusted interfaces connected to the 
end-user and trusted interfaces connected to the DHCP server or another switch. 

 

To enable the DHCP snooping on the system, use the following command 

Enables the DHCP snooping on the system. 

Global 

Disables the DHCP snooping on the system. (default) 

 

Upon entering the ip dhcp snooping command, the DHCP_OFFER and DHCP_ACK 
messages from all the ports will be discarded before specifying a trusted port. 

To enable the DHCP snooping on a VLAN, use the following command 

 VLANS 

Enables the DHCP snooping on a specified VLAN. 

 

 

Global 

Disables the DHCP snooping on a specified VLAN. 

 

You must enable DHCP snooping on the system before enabling DHCP snooping on a 
VLAN. 

 

To define a state of a port as trusted or untrusted, use the following command. 

 PORTS 

Defines a state of a specified port as trusted. 

 

 

Global 

Defines a state of a specified port as untrusted. 

 

Note that, the DHCP snooping only sees the DHCP_OFFER and DHCP_ACK messages 
which are received from untrusted interfaces.