Dell PowerEdge VRTX - Manual (Page 387)

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FILE LOCATION: C:\Users\gina\Desktop\Checkout_new\Dell Plasma\User
Guide\Plasma_UGSwitching_DHCP.fm
D E L L CO N F I D E N T I A L – P R E L I MI N A RY 4/ 1 8 /1 3 - F O R PR O O F O N LY
As shown in Table 17-1, the DHCP Snooping Binding database is updated by
interception of DHCPACK, DHCPDECLINE and DHCPRELEASE packets,
and is stored in non-volatile memory.
Even if a port is down, its entries are not deleted.
NOTE: Only DHCP requests on untrusted ports are maintained in the Binding
database.
Limitations
The following limitations apply:
• Enabling DHCP snooping uses TCAM resources.
• The switch writes changes to the binding database only when the switch
system clock is synchronized with SNTP.
• The switch does not update the Binding database when a station moves to
another interface.
Global Parameters
Use the Global Parameters page to:
• Enable/disable DHCP snooping globally.
• Determine whether to forward or filter DHCP packets received from
untrusted interfaces, whose source MAC address and the DHCP client
MAC address do not match.
• Determine whether to forward or filter DHCP packets, received from
untrusted interfaces, with option-82 information.
• Set Binding database update interval.
To configure DHCP snooping on the device:
1 Click Switching > DHCP Snooping > Global Parameters in the tree view
to display the Global Parameters page.
2 Enable/disable DHCP snooping on the device in the DHCP Snooping
Status field.
3 If DHCP snooping is enabled, enter the fields:
– Option 82 Passthrough — Enable/disable whether to forward (enable)
or filter (disable) DHCP packets, received from untrusted interfaces,
with option-82 information.