XMG1930 Series User’s Guide
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The following table describes the labels in this screen.
26.4 Technical Reference
This section provides technical background information on the topics discussed in this chapter.
26.4.1 DHCP Snooping Overview
Use DHCP snooping to filter unauthorized DHCP packets on the network and to build the binding table
dynamically. This can prevent clients from getting IP addresses from unauthorized DHCP servers.
26.4.1.1 Trusted vs. Untrusted Ports
Every port is either a trusted port or an untrusted port for DHCP snooping. This setting is independent of
the trusted or untrusted setting for ARP inspection. You can also specify the maximum number for DHCP
packets that each port (trusted or untrusted) can receive each second.
Trusted ports are connected to DHCP servers or other switches. The Switch discards DHCP packets from
trusted ports only if the rate at which DHCP packets arrive is too high. The Switch learns dynamic
bindings from trusted ports.
Table 107 Advanced Application > DHCP Snooping > Configure > VLAN > Port
LABEL
DESCRIPTION
VID
Enter the ID number of the VLAN you want to configure here.
Port
Enter the number of ports to which you want to apply the specified DHCP option 82 profile.
You can enter multiple ports separated by (no space) comma (,) or hyphen (–). For
example, enter “3–5” for ports 3, 4, and 5. Enter “3,5,7” for ports 3, 5, and 7.
Option 82 Profile
Select a pre-defined DHCP option 82 profile that the Switch applies to the specified ports in
this VLAN. The Switch adds the information (such as slot number, port number, VLAN ID and/
or system name) specified in the profile to DHCP requests that it broadcasts to the DHCP
VLAN, if specified, or VLAN. You can specify the DHCP VLAN in the
DHCP Snooping
Configure
screen.
The profile you select here has priority over the one you select in the
DHCP Snooping
>
Configure
>
VLAN
screen.
Add
Click this to create a new entry or to update an existing one.
This saves your changes to the Switch’s run-time memory. The Switch loses these changes if
it is turned off or loses power, so use the
Save
link on the top navigation panel to save your
changes to the non-volatile memory when you are done configuring.
Cancel
Click this to reset the values above based on the last selected entry or, if not applicable, to
clear the fields above.
Clear
Click
Clear
to reset the fields to the factory defaults.
Index
This field displays a sequential number for each entry. Click an index number to change the
settings.
VID
This field displays the VLAN to which the ports belong.
Port
This field displays the ports to which the Switch applies the settings.
Profile Name
This field displays the DHCP option 82 profile
that the Switch applies to the ports.
Delete
Select the entries that you want to remove in the
Delete
column, then click the
Delete
button to remove the selected entries from the table.
Cancel
Click this to clear the
Delete
check boxes above.
