You can configure general DHCP service properties and change some default values. The following sections describe the DHCP service properties that you can configure:
- Configuring Automated Scope Management
- Configuring DHCP Fingerprint Rules
Configuring Automated Scope Management
BloxOne DDI provides global parameters that can assist you in streamlining the management of your IP scopes and networks. Based on the configuration of these parameters, BloxOne DDI analyzes the data and provides suggestions on how you can scale your subnets in advance. You can preview these suggestions and decide whether you want to accept, decline, or modify them. For example, if the threshold parameter is set at 90%, address space increase at 20%, and unused IPs at 10%, it means that BloxOne DDI will suggest how you can expand the affected subnet by 20% and retain 10% of unused addresses outside of DHCP when the subnet usage reaches or exceeds the threshold of 90%. For information about how to review the suggested options and take actions, see Resizing DHCP Scopes. In addition, you can enable notifications, so the Cloud Service Portal can display an alert icon next to the respective subnets and their ancestors (such as the IP spaces and address blocks) when the network usage reaches or exceeds the configured threshold.
In this release, BloxOne DDI provides the following suggestions on how you can manage your subnets:
- Expand or create a DHCP address range.
- Expand a subnet one bit at a time by expanding an existing range.
- Suppress notifications based on your business needs.
When you expand or update a subnet, you must adjust your routing configuration. In addition, there is no support for shared or overlapping subnets in the suggested options.
To configure global parameters that BloxOne DDI uses to project suggestions, complete the following:
From the Cloud Services Portal, click Manage -> IPAM/DHCP -> Global DHCP Configuration.
On the Global DHCP Configuration page, expand Automated Scope Management,and complete the following:
Enable Automated Scope Management: Select this check box to configure parameters that BloxOne DDI uses to analyze your network usage and provide suggestions about your address scope management.
Enable Notifications: Select this check box so the Cloud Services Portal can display an alert icon next to the subnets when they require attention based on the parameters you have configured. You can disable notifications so the alert icon will not show up even when attention is required. You can also turn off notifications temporarily and re-enable it for a later date by selecting a date in the Re-enable Notifications field.
Trend Line Threshold: This field displays the current threshold for subnet usage. The default is 90%. You can change the default value by entering a different percentage.
Note title Note
BloxOne DDI validates the threshold four times a day. When the subnet usage reaches or exceeds the threshold at the time when BloxOne DDI performs the validation, the portal displays the alert icon next to the respective subnet. The portal removes the icon if the usage falls below the threshold during the next validation time.
- Increase DHCP Range Address Space: This field shows the percentage or the number of addresses a subnet will expand when its usage reaches or exceeds the threshold. The default is 20%. You can override the default by setting a specific percentage or a number of addresses for the expansion. If you are configuring this at the global or IP space level, using a percentage is more effective. For a specific subnet, however, you can select a specific number of addresses you want to add. Ensure that you select the corresponding unit from the drop-down menu while entering the value.
Unused IP Reservation: This is the number of unused IP addresses that you want to retain within the subnet and are not associated with any DHCP usage (such as ranges, fixed addresses, and others). The default is 10%. When you override the default, ensure that you take into consideration the parameter for the DHCP range increase so the numbers align properly for your subnets.
Note title Note
BloxOne DDI validates the parameters four times a day. When any of these parameters create concerns for any of the subnets, the portal displays the alert icon next to the respective subnets, so you can preview the suggested options for expanding your subnets. For more information, see Resizing DHCP Scopes.
Click Save & Close to save the configuration or click Cancel to exit.
Defining Lease Times
A DHCP lease time specifies the amount of time that the DHCP server grants to a network device the permission to use a particular IP address. There are a number of factors to consider when setting the lease time for IP addresses, such as the types of resources and clients on the network, and impact to traffic and performance.