ZyXEL MES3500-24F User Guide - Page 223

Advanced Application > IP Source Guard, > DHCP Snooping > Con

Page 223 highlights

Chapter 26 IP Source Guard still available after a restart. To open this screen, click Advanced Application > IP Source Guard > DHCP Snooping > Configure. Figure 115 DHCP Snooping Configure The following table describes the labels in this screen. Table 78 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: The Switch will drop all DHCP requests if you enable DHCP snooping and there are no trusted ports. 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 225) to help the DHCP servers distinguish between DHCP requests from different VLAN. Database Agent URL Timeout interval Write delay interval 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. MES3500-24/24F User's Guide 223

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Chapter 26 IP Source Guard
MES3500-24/24F User’s Guide
223
still available after a restart. To open this screen, click
Advanced Application > IP Source Guard
> DHCP Snooping > Configure
.
Figure 115
DHCP Snooping Configure
The following table describes the labels in this screen.
Table 78
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: The Switch will drop all DHCP requests if you enable DHCP snooping and there are
no trusted ports.
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 225
) 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.