User's Manual

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VLAN will be rejected if their source MAC addresses and source IP addresses do not match up with the
configured MAC-to-IP binding relationship. The binding relationship on an interface can be dynamically bound
by DHCP or configured manually. If no MAC addresses are bound to IP addresses on a physical interface, the
switch rejects forwarding all IP packets received from the physical interface.
Run the following commands in global configuration mode.
Command Operation
ip verify source vlan vlanid
Enables source IP address checkup on all distrusted interfaces
in a VLAN.
no ip verify source vlan vlanid
Disables source IP address checkup on all interfaces in a VLAN.
Note: If the DHCP packet (also the IP packet) is received, it will be forwarded because global snooping is
configured.
44.1.9 Setting an Interface to the One Which is Trusted by IP Source
Address Monitoring
The source address detection function will not be enabled for the IP source address trust interface.
Run the following commands in interface configuration mode.
Command Operation
ip-source trust Sets an interface to the one with a trusted source IP
address.
no ip-source trust Resumes an interface to the one with a distrusted source
IP address.
44.1.10 Setting DHCP Snooping Option 82
Option 82 brings the local information to a server and helps the server to distribute addresses to clients.
Run the following commands in the global configuration mode.
Command Operation
ip dhcp-relay snooping
information option
Sets that option82, which is in the default format, is
carried when DHCP-snooping forwards the DHCP
packets.
no ip dhcp-relay snooping
information option
Sets that option82 is not carried when DHCP-snooping
forwards the DHCP packets.
To specify the format of option82, conduct the following settings in global mode.
Command Operation
ip dhcp-relay snooping
information option format
Sets the format of option82 that the DHCP packets carry
when they are forwarded by DHCP-Snooping.