ZyXEL Communications MGS-3712, User Manual

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Chapter 23 IP Source Guard
MGS-3712/MGS-3012F User’s Guide
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23.5.1 DHCP Snooping Port Configure
Use this screen to specify whether ports are trusted or untrusted ports for DHCP snooping.
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If DHCP is enabled and there are no trusted ports, DHCP requests will not
succeed.
You can also specify the maximum number for DHCP packets that each port (trusted or
untrusted) can receive each second. To open this screen, click
Advanced Application > IP
Source Guard > DHCP Snooping > Configure > Port .
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, tftp://192.168.10.1/database.txt .
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 23.4 on page 191 ).
Apply Click Apply to save 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 in this screen to their last-saved values.
Table 68 DHCP Snooping Configure (continued)
LABEL DESCRIPTION