D-Link DGS-1250 Emulator - Page 128

ip dhcp snooping database

Page 128 highlights

DGS-1250 Series Gigabit Ethernet Smart Managed Switch CLI Reference Guide Usage Guideline The DHCP snooping function validates the DHCP packets when it arrives at the port on the VLAN that is enabled for DHCP snooping. By default, the validation process will drop the packet if the gateway address is not equal to 0 or Option 82 is present. Use this command to allow or deny packets with the relay Option 82 arriving at the untrusted interface. Example This example shows how to enable DHCP snooping for Option 82 to allow untrusted ports. Switch# configure terminal Switch(config)# ip dhcp snooping information option allow-untrusted Switch(config)# 16-3 ip dhcp snooping database This command is used to configure the storing of DHCP snooping binding entries to a remote site. Use the no form of this command to disable the storing or reset the parameters to the default setting. ip dhcp snooping database {URL | write-delay SECONDS} no ip dhcp snooping database [write-delay] Parameters URL write-delay SECONDS Specifies the URL in the following form:  tftp://location/filename Specifies the time delay to write the entries after a change is seen in the binding entry. The default is 300 seconds. The range is from 60 to 86400. Default By default, the URL for the database agent is not defined. The write delay value is set to 300 seconds. Command Mode Global Configuration Mode. Usage Guideline Use this command to store the DHCP binding entry to a remote server. Use the follow method to store DHCP binding entries:  tftp: Store the entries to remote site via TFTP. The lease time of the entry will not be modified and the live time will continue to be counted while the entry is provisioned. Example This example shows how to store the binding entry to a file in the file system. Switch# configure terminal Switch(config)# ip dhcp snooping database tftp: //10.0.0.2/store/dhcp-snp-bind Switch(config)# 125

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DGS-1250 Series Gigabit Ethernet Smart Managed Switch CLI Reference Guide
125
Usage Guideline
The DHCP snooping function validates the DHCP packets when it arrives at the port on the VLAN that is enabled
for DHCP snooping. By default, the validation process will drop the packet if the gateway address is not equal to 0
or Option 82 is present.
Use this command to allow or deny packets with the relay Option 82 arriving at the untrusted interface.
Example
This example shows how to enable DHCP snooping for Option 82 to allow untrusted ports.
Switch# configure terminal
Switch(config)# ip dhcp snooping information option allow-untrusted
Switch(config)#
16-3
ip dhcp snooping database
This command is used to configure the storing of DHCP snooping binding entries to a remote site. Use the no form
of this command to disable the storing or reset the parameters to the default setting.
ip dhcp snooping database {
URL
| write-delay
SECONDS
}
no ip dhcp snooping database [write-delay]
Parameters
URL
Specifies the URL in the following form:
tftp://location/filename
write-delay
SECONDS
Specifies the time delay to write the entries after a change is seen in the binding
entry. The default is 300 seconds. The range is from 60 to 86400.
Default
By default, the URL for the database agent is not defined.
The write delay value is set to 300 seconds.
Command Mode
Global Configuration Mode.
Usage Guideline
Use this command to store the DHCP binding entry to a remote server. Use the follow method to store DHCP
binding entries:
tftp: Store the entries to remote site via TFTP.
The lease time of the entry will not be modified and the live time will continue to be counted while the entry is
provisioned.
Example
This example shows how to store the binding entry to a file in the file system.
Switch# configure terminal
Switch(config)# ip dhcp snooping database tftp: //10.0.0.2/store/dhcp-snp-bind
Switch(config)#