H3C Technologies H3C S3100 Series Switches - Manual (Page 538)

3-6
DHCP Snooping Configuration
Configuring DHCP Snooping
Follow these steps to configure DHCP snooping:
Operation Command Description
Enter system view system-view —
Enable DHCP snooping dhcp-snooping
Required
By default, the DHCP snooping function
is disabled.
z After DHCP snooping is enabled on an S3100 Ethernet switch, clients connected with this switch
cannot obtain IP addresses dynamically through BOOTP.
z You are not recommended to configure both the DHCP snooping and selective Q-in-Q function on
an S3100-EI switch, which may result in the DHCP snooping to function abnormally.
Configuring DHCP Snooping Trusted/Untrusted Ports
Follow these steps to configure DHCP Snooping Trusted/Untrusted Ports:
Operation Command Description
Enter system view system-view —
Enter Ethernet port view
interface interface-type
interface-number
—
Specify the current port
as a trusted port
dhcp-snooping trust
Required
By default, after DHCP snooping is
enabled, all ports of the S3100-EI switch
are untrusted ports.
z Only the S3100-EI series among S3100 series switches support the configuration of DHCP
snooping trusted ports.S3100-SI series Ethernet switches do not support the configuration of
DHCP snooping trusted ports. That is, after DHCP snooping is enabled, all ports of the S3100-SI
series Ethernet switches are trusted ports.
z After DHCP snooping is enabled, all ports of an S3100-EI switch are untrusted ports. You need to
specify the port of the S3100-EI switch connected to the valid DHCP server as trusted to ensure
that DHCP clients can obtain valid IP addresses. The trusted port and the port connected to the
DHCP clients must be in the same VLAN.