Web Management Guide-R04

Table Of Contents
Chapter 12
| Security Measures
DHCPv4 Snooping
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DHCP Snooping Information Option Remote ID TR101 VLAN Field – Adds
“:VLAN” in TR101 field for untagged packets. (Default: Enabled)
The format for TR101 option 82 is: “<IP> eth <SID>/<PORT>[:<VLAN>]”. Note
that the SID (Switch ID) is always 0. By default the PVID is added to the end of
the TR101 field for untagged packets. For tagged packets, the VLAN ID is always
added.
DHCP Snooping Information Option TR101 Board ID – Sets the board
identifier used in Option 82 information based on TR-101 syntax. (Range: 0-9;
Default: undefined)
DHCP Snooping Information Option Policy – Specifies how to handle DHCP
client request packets which already contain Option 82 information.
Drop – Drops the client’s request packet instead of relaying it.
Keep – Retains the Option 82 information in the client request, and
forwards the packets to trusted ports.
Replace – Replaces the Option 82 information circuit-id and remote-id
fields in the client’s request with information about the relay agent itself,
inserts the relay agent’s address (when DHCP snooping is enabled), and
forwards the packets to trusted ports. (This is the default policy.)
Web Interface
To configure global settings for DHCP Snooping:
1. Click IP Service, DHCP, Snooping.
2. Select Configure Global from the Step list.
3. Select the required options for the general DHCP snooping process and for the
DHCP snooping information options.
4. Click Apply