324
# Enable DHCP snooping.
<Device> system-view
[Device] dhcp-snooping
# Configure port Ethernet 1/0/2, which is connected to the DHCP server, as a trusted port.
[Device] interface ethernet1/0/2
[Device-Ethernet1/0/2] dhcp-snooping trust
[Device-Ethernet1/0/2] quit
2. Configure the IPv4 source guard function.
# Configure the IPv4 source guard function on port Ethernet 1/0/1 to filter packets based on both the
source IP address and MAC address.
[Device] interface ethernet1/0/1
[Device-Ethernet1/0/1] ip verify source ip-address mac-address
[Device-Ethernet1/0/1] quit
Verifying the configuration
# Display the IPv4 source guard binding entries generated on port Ethernet 1/0/1.
[Device] display ip source binding
Total entries found: 1
MAC Address IP Address VLAN Interface Type
0001-0203-0406 192.168.0.1 1 Eth1/0/1 DHCP-SNP
# Display DHCP snooping entries to see whether they are consistent with the dynamic entries generated
on Ethernet 1/0/1.
[Device] display dhcp-snooping
DHCP Snooping is enabled.
The client binding table for all untrusted ports.
Type : D--Dynamic , S--Static , R--Recovering
Type IP Address MAC Address Lease VLAN SVLAN Interface
==== =============== ============== ============ ==== ===== =================
D 192.168.0.1 0001-0203-0406 86335 1 N/A Ethernet1/0/1
--- 1 dhcp-snooping item(s) found ---
The output shows that a dynamic IPv4 source guard entry has been generated based on the DHCP
snooping entry.
Dynamic IPv4 source guard binding by DHCP relay
configuration example
Network requirements
As shown in Figure 122, the host and the DHCP server are connected to the switch through interfaces
VLAN-interface 100 and VLAN-interface 200 respectively. DHCP relay is enabled on the switch. The host
(with the MAC address of 0001-0203-0406) obtains an IP address from the DHCP server through the
DHCP relay agent.
Enable the IPv4 source guard binding function on the switch’s VLAN-interface 100 to filter packets based
on the DHCP relay entry, allowing only packets from clients that obtain IP addresses from the DHCP
server to pass.