SignaMax 065-7851, User Manual

Page: 231 / 365

Publication date:Oct., 2012
Revision A2
229
Trust port 2 : It set a trust port 2. available port from 0 to 24. 0 is disabled.
Trust VID
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It set a trust VLAN ID. available VID from 1 to 4094.
Server IP
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It set a trust DHCP Server IP address for DHCP Snooping.
Option 82
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： ：
：
It set the DHCP Option 82 function on the switch, default is
Disable.
Action
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It set the switch when received a client DHCP request packet then
action for filtering. available action : keep/ drop / replace.
Note
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Filtering rules are implemented as follows:
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If the DHCP snooping is disabled, all DHCP packets are forwarded.
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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.
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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.
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If a DHCP packet from a client passes the filtering criteria above, it
will only be forwarded to trusted ports in the same VLAN.
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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.
3-18-3. DHCP Snooping Client
Function name:
DHCP Snooping Client
Function description:
To show the DHCP snooping client.