ZyXEL MGS-3712F User Guide - Page 247

Table 77

Page 247 highlights

Chapter 26 IP Source Guard The following table describes the labels in this screen. Table 77 DHCP Snooping Configure LABEL DESCRIPTION Active Select this to enable DHCP snooping on the Switch. You still have to enable DHCP snooping on specific VLAN and specify trusted ports. DHCP Vlan Note: If DHCP is enabled and there are no trusted ports, DHCP requests will not succeed. Select a VLAN ID if you want the Switch to forward DHCP packets to DHCP servers on a specific VLAN. Note: You have to enable DHCP snooping on the DHCP VLAN too. Database Agent URL Timeout interval Write delay interval Renew DHCP Snooping URL You can enable Option82 in the DHCP Snooping VLAN Configure screen (Section 26.5.2 on page 249) to help the DHCP servers distinguish between DHCP requests from different VLAN. Select Disable if you do not want the Switch to forward DHCP packets to a specific VLAN. If Timeout interval is greater than Write delay interval, it is possible that the next update is scheduled to occur before the current update has finished successfully or timed out. In this case, the Switch waits to start the next update until it completes the current one. Enter the location of the DHCP snooping database. The location should be expressed like this: tftp://{domain name or IP address}/directory, if applicable/file name; for example, tftp://192.168.10.1/database.txt. Enter how long (10-65535 seconds) the Switch tries to complete a specific update in the DHCP snooping database before it gives up. Enter how long (10-65535 seconds) the Switch waits to update the DHCP snooping database the first time the current bindings change after an update. Once the next update is scheduled, additional changes in current bindings are automatically included in the next update. Enter the location of a DHCP snooping database, and click Renew if you want the Switch to load it. You can use this to load dynamic bindings from a different DHCP snooping database than the one specified in Agent URL. When the Switch loads dynamic bindings from a DHCP snooping database, it does not discard the current dynamic bindings first. If there is a conflict, the Switch keeps the dynamic binding in volatile memory and updates the Binding collisions counter in the DHCP Snooping screen (Section 26.4 on page 243). MGS-3712/MGS-3712F User's Guide 247

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Chapter 26 IP Source Guard
MGS-3712/MGS-3712F User’s Guide
247
The following table describes the labels in this screen.
Table 77
DHCP Snooping Configure
LABEL
DESCRIPTION
Active
Select this to enable DHCP snooping on the Switch. You still have
to enable DHCP snooping on specific VLAN and specify trusted
ports.
Note: If DHCP is enabled and there are no trusted ports,
DHCP requests will not succeed.
DHCP Vlan
Select a VLAN ID if you want the Switch to forward DHCP packets
to DHCP servers on a specific VLAN.
Note: You have to enable DHCP snooping on the DHCP
VLAN too.
You can enable
Option82
in the
DHCP Snooping VLAN
Configure
screen (
Section 26.5.2 on page 249
) to help the DHCP
servers distinguish between DHCP requests from different VLAN.
Select
Disable
if you do not want the Switch to forward DHCP
packets to a specific VLAN.
Database
If
Timeout interval
is greater than
Write delay interval
, it is
possible that the next update is scheduled to occur before the
current update has finished successfully or timed out. In this
case, the Switch waits to start the next update until it completes
the current one.
Agent URL
Enter the location of the DHCP snooping database. The location
should be expressed like this:
tftp://{domain name or IP
address}/directory, if applicable/file name
; for example,
.
Timeout interval
Enter how long (10-65535 seconds) the Switch tries to complete
a specific update in the DHCP snooping database before it gives
up.
Write delay
interval
Enter how long (10-65535 seconds) the Switch waits to update
the DHCP snooping database the first time the current bindings
change after an update. Once the next update is scheduled,
additional changes in current bindings are automatically included
in the next update.
Renew DHCP
Snooping URL
Enter the location of a DHCP snooping database, and click
Renew
if you want the Switch to load it. You can use this to load dynamic
bindings from a different DHCP snooping database than the one
specified in
Agent URL
.
When the Switch loads dynamic bindings from a DHCP snooping
database, it does not discard the current dynamic bindings first. If
there is a conflict, the Switch keeps the dynamic binding in
volatile memory and updates the
Binding collisions
counter in
the
DHCP Snooping
screen (
Section 26.4 on page 243
).