You can exclude IP addresses in the subnets used in your installation to prevent SDDC Manager from assigning those addresses to resources.
SDDC Manager allocates IP addresses to resources from the subnets you enter during the Cloud Foundation bring-up process or during the workload domain creation process. When those subnets include IP address that are already used in your corporate network for other purposes, or which you want to reserve for another use, you exclude those IP addresses to prevent IP conflicts.
SDDC Manager has two types of exclusions:
Global exclusions are persistent and are configured using the IP Exclusions area on the IP Distribution screen. See IP Distribution Screen.
Local exclusions are valid until another local exclusion is subsequently created for that subnet's addresses. For each subnet, the most recent local exclusion overwrites the earlier one. Local exclusions are created by the bring-up process and the VI workload domain creation workflow.
For example, during the bring-up process on the first rack in a Cloud Foundation installation, specifying excluded IP addresses in the management subnet screen of the bring-up wizard prevents the software from using those excluded IP addresses as it assigns management IPs to the physical and logical resources involved in this process, such as the ESXi hosts in the rack, the management domain and the virtual appliances, and so on. The list of excluded IP addresses is saved.
Then, during creation of a VI workload domain, the software uses the same management network subnet that was used during bring-up process. When you specify excluded IP addresses for the management network subnet in the VI workload domain creation wizard, that list of excluded IP addresses replaces the excluded IP addresses that were entered during the bring-up process.