3Com Switch 7757, Руководство по настройке

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618 C
HAPTER
58: DHCP R
ELAY
A
GENT
C
ONFIGURATION
Specifying address checking fields
After enabled with the address checking function, Switch 7750 Ethernet switches
default to check the IP address, MAC address, VLAN ID, and port number of a
DHCP client respectively. The DHCP client can access external networks only after
an entry matching all the four fields is found in the client address table.
You can disable some fields (MAC address, VLAN ID, or port number) from address
checking as needed. Thus, after enabled with address checking, the DHCP relay
agent will not check the disabled fields, so that the clients not matching all the
fields can also access external networks.
n
If you configure a static client address entry on the DHCP relay agent using the
dhcp-security static command without specifying the vlan or port keyword, the
DHCP relay agent will not check the VLAN ID or port number when performing
address checking for the client, even if the two fields are enabled for address
checking.
Configuring dynamic entries
Through this configuration task, you can validate or invalidate the dynamic
IP-to-MAC mapping entries generated by the DHCP relay agent. DHCP client
addresses are matched based on the dynamic entries generated by DHCP relay
agent only after these entries are activated; otherwise, DHCP client addresses are
matched based only on the security address entries statically configured.
Table 490 Specify address checking fields
Operation Command Description
Enter system view system-view -
Enter interface view interface interface-type
interface-number
-
Specify address checking
field(s) address-check field { mac | vlan |
port } enable
Optional
By default, after
enabled with the
address checking
function, the DHCP
relay agent checks the
IP address, MAC
address, VLAN ID, and
port number of a
DHCP client
respectively.
Disable specified address
checking field(s) address-check field { mac | vlan |
port } disable
Table 491 Configure dynamic entries generated by DHCP relay agents
Operation Command Description
Enter system view system-view -
Enter VLAN interface
view interface interface-type
interface-number
-
Validate the dynamic
entries generated by
the DHCP relay agent address-check dhcp-relay
enable Optional
By default, the dynamic IP-to-MAC
mapping entries generated by the
DHCP relay agent are valid