AirLive SNMP-24MGB - Manual (Page 181)

4. Web Management in SNMP-24MGB
AirLive SNMP-24MGB v2 User’s Manual 174
Trust port 2:
It set a trust port 2 available port from 0 to 24. 0 is disabled.
Trust VID:
It set a trust VLAN ID available VID from 1 to 4094.
Server IP: It set a trust DHCP Server IP address for DHCP Snooping.
Option 82: It set the DHCP Option 82 function on the switch, default is Disable.
Action:
It set the switch when received a client DHCP request packet then action for
filtering available action : keep/ drop / replace.
Note: Filtering rules are implemented as follows:
-
If the DHCP snooping is disabled, all DHCP packets are forwarded.
-
If DHCP snooping is enabled and also enabled on the VLAN where the DHCP
packet is received, all DHCP packets are forwarded for a trusted port.
-
If DHCP snooping is enabled and also enabled on the VLAN where the DHCP
packet is received, but the port is not trusted, it is processed as follows:
„ If the DHCP packet is a reply packet from a DHCP server, the packet is
dropped.
„ If the DHCP packet is from a client, such as a DISCOVER, REQUEST
INFORM, DECLINE or RELEASE message, the packet is forwarded if MAC
address verification is disabled. However, if MAC address verification is
enabled, then the packet will only be forwarded if the client’s hardware
address stored in the DHCP packet is the same as the source MAC address
in the Ethernet header.
„ If the DHCP packet is not a recognizable type, it is dropped.
-
If a DHCP packet from a client passes the filtering criteria above, it will only be
forwarded to trusted ports in the same VLAN.
-
If a DHCP packet is from server is received on a trusted port, it will be forwarded to
both trusted and un-trusted ports in the same VLAN.
4.18.3 DHCP Snooping Client
Function name:
DHCP Snooping Client
Function description:
To show the DHCP snooping client.