ZyXEL Communications MES3500-24 User Manual

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Chapter 26 IP Source Guard
MES3500-24/24F User’s Guide
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26.5  DHCP Snooping Configure
Use this screen to enable DHCP snooping on the Switch (not on specific VLAN), specify the VLAN 
where the default DHCP server is located, and configure the DHCP snooping database. The DHCP 
snooping database stores the current bindings on a secure, external TFTP server so that they are 
Last ignored bindings 
counters
This section displays the number of times and the reasons the Switch ignored 
bindings the last time it read bindings from the DHCP binding database. You can clear 
these counters by restarting the Switch or using CLI commands. See the Ethernet 
Switch CLI Reference Guide.
Binding collisions
This field displays the number of bindings the Switch ignored because the Switch 
already had a binding with the same MAC address and VLAN ID.
Invalid interfaces
This field displays the number of bindings the Switch ignored because the port 
number was a trusted interface or does not exist anymore.
Parse failures
This field displays the number of bindings the Switch ignored because the Switch was 
unable to understand the binding in the DHCP binding database.
Expired leases
This field displays the number of bindings the Switch ignored because the lease time 
had already expired.
Unsupported vlans
This field displays the number of bindings the Switch ignored because the VLAN ID 
does not exist anymore.
Last ignored time
This field displays the last time the Switch ignored any bindings for any reason from 
the DHCP binding database.
Total ignored bindings 
counters
This section displays the reasons the Switch has ignored bindings any time it read 
bindings from the DHCP binding database. You can clear these counters by restarting 
the Switch or using CLI commands. See the Ethernet Switch CLI Reference Guide.
Binding collisions
This field displays the number of bindings the Switch has ignored because the Switch 
already had a binding with the same MAC address and VLAN ID.
Invalid interfaces
This field displays the number of bindings the Switch has ignored because the port 
number was a trusted interface or does not exist anymore.
Parse failures
This field displays the number of bindings the Switch has ignored because the Switch 
was unable to understand the binding in the DHCP binding database.
Expired leases
This field displays the number of bindings the Switch has ignored because the lease 
time had already expired.
Unsupported vlans
This field displays the number of bindings the Switch has ignored because the VLAN 
ID does not exist anymore.
Table 77   
DHCP Snooping (continued)
LABEL
DESCRIPTION