Chapter 25 IP Source Guard
GS1920 Series User’s Guide
207
Figure 149   Advanced Application > IP Source Guard > DHCP Snooping > Configure
The following table describes the labels in this screen.
Table 92   Advanced Application > IP Source Guard > 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 25.5.2 on page 210) 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, 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.