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A DHCP exclusion range is a specified range of IP addresses residing within a DHCP range. An exclusion range is defined as a start/end IP address pair within an ipam/range object and is considered a sub-object within a regular DHCP range. IP addresses residing within the exclusion range are excluded from the pool of available IP addresses and are un-leasable. The DHCP server is prevented from assigning IP addresses within the exclusion range to network devices.

There can be multiple exclusion ranges within a DHCP range, but the exclusion range must be fully contained within a DHCP range. The exclusion range cannot overlap other exclusion ranges within the DHCP range. IP addresses within an exclusion range are excluded from being allocated as a DHCP lease unless a DHCP address already exists on the specific address. You can define an exclusion range, or multiple exclusion ranges, within a DHCP range. 

IP addresses residing within an exclusion range are labeled as DHCP Exclusion Range. An exclusion range can be created on already leased addresses, but the existing leases will not be renewed.

When an IP address is created that is both a member of an exclusion range and is a fixed address, the fixed address takes precedence over the range. By designating an IP address as a fixed address, the IP address is removed from the exclusion range. Similarly, when an exclusion range is created within a DHCP range, the exclusion range is removed from the DHCP range.

For information on creating address ranges, see Configuring Address Ranges.

Valid and Invalid DHCP Exclusion Ranges

The following table describes a parent DHCP range of 192.168.1 0/24

Valid


192.168.1.1

Fixed Address (FA), Exclusion Range, DHCP Range

192.168.1.2  

Reservation, Exclusion Range, DHCP Range

192.168.1.3 

Exclusion Range, DHCP Range

192.168.1.4

FA

192.168.1.5

Reservation

192.168.1.6..10 

IPAM Range

192.168.1.11..20  

DHCP Range

Not Valid


192.168.2.1

Exclusion Range (this must be part of the parent object)

Viewing a DHCP Exclusion Range

To view the list of DHCP Exclusion ranges, complete the following:

  • From the Cloud Services Portal, click Manage -> IPAM/DHCP -> Address Spaces.
  • Click IP Space -> Address Block -> Subnet -> corresponding Range and click the respective range link.
  • From among the State options in the filters section, select Free to view all IP Addresses contained within the exclusion range. All IP addresses residing within an exclusion range will be labeled Exclusion Range.  
  • The information for each IP address in the exclusion range is displayed as follows:
    • Address/Name: Displays start and end addresses of the address range.
    • Description: Additional information about the address range.
    • Usage: The usage of the address range (Fixed Address, DHCP Range, or Exclusion Range). An address within an exclusion range will have "Exclusion Range" as usage and will lose its DHCP Range usage. It is also possible that it will be combined with other usages such as Fixed Address, DHCP Range, and Exclusion Range, always in mutually exclusive scenarios.

You can click on an individual IP address within the exclusion range to view the details for the respective IP Address.

Creating DHCP Exclusion Ranges

Note

DHCP exclusion ranges must be added through the Range editor. For information on creating address ranges and using the Range editor, seeConfiguring Address Ranges.

To create a DHCP exclusion range, complete the following:

  1. From the Cloud Services Portal, click Manage -> IPAM/DHCP -> Address Spaces.
  2. Click IP Space -> Address Block -> Subnet -> corresponding Range.
  3. On the Range page, select Exclusion Range from the Create drop-down list.
  4. On the Create Range page, under DHCP Exclusion Ranges, click Add and specify the following:
    • Start Address: Enter the first IP address in the exclusion range.
    • End Address: Enter the last IP address in the exclusion range.
    • Comment: Enter a comment about the exclusion range.

Click Save & Close to save the created exclusion range.

Removing Exclusion Ranges

To remove a DHCP exclusion range, complete the following:

  1. From the Cloud Services Portal, click Manage -> IPAM/DHCP -> Address Spaces.
  2. Click IP Space -> Address Block -> Subnet -> corresponding Range.
  3. On the Range page, select Exclusion Range from the Create drop-down list.
  4. On the Create Range page, under DHCP Exclusion Ranges, select the exclusion range to be removed.
  5. Click Remove to remove the exclusion range.

Click Save & Close to save the updated exclusion range configuration.

Modifying Exclusion Ranges

To modify a DHCP exclusion range, complete the following:

  1. From the Cloud Services Portal, click Manage -> IPAM/DHCP -> Address Spaces.
  2. Click IP Space -> Address Block -> Subnet -> the corrresponding Range.
  3. On the Range page, select the Exclusion Range to be modified.
  4. On the Edit Range page, under DHCP Exclusion Rangesselect the exclusion range to be modified.
  5. Click Edit to edit or modify the existing exclusion range.

Click Save & Close to save the modified exclusion range configuration.


 

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