HP V1910 manual Application environment of trusted ports, Configure trusted and untrusted ports

Application environment of trusted ports

Configuring a trusted port connected to a DHCP server

a.Configure trusted and untrusted ports

As shown in a, a DHCP snooping device’s port that is connected to an authorized DHCP server should be configured as a trusted port to forward reply messages from the DHCP server, so that the DHCP client can obtain an IP address from the authorized DHCP server.

Configuring trusted ports in a cascaded network

In a cascaded network involving multiple DHCP snooping devices, the ports connected to other DHCP snooping devices should be configured as trusted ports.

To save system resources, you can disable the trusted ports, which are indirectly connected to DHCP clients, from recording clients’ IP-to-MAC bindings upon receiving DHCP requests.

a.Configure trusted ports in a cascaded network

DHCP client
Host A	DHCP snooping
	Switch A		GE1/0/1
	GE1/0/1	GE1/0/2	GE1/0/4
DHCP client	GE1/0/3		GE1/0/3
Host B
	GE1/0/1
	GE1/0/4	GE1/0/2

DHCP client	GE1/0/3	DHCP snooping
		Switch B
Host C

DHCP client

Host D

DHCP server

GE1/0/2 GE1/0/1

DHCP snooping

Switch C

Untrusted ports

Trusted ports disabled from recording binding entries Trusted ports enabled to record binding entries

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