I had trouble discovering servers on a different subnet so after a little digging, I found the below which did the trick.
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2014366
After installing the VMware Capacity Planner Datamanager and configuring the system to receive new systems, you can perform these steps to discover systems on an IP subnet:
- Open Capacity Planner Data Manager.
- Navigate to Admin > Options.
- Go to Modules > Discover > Settings.
- Deselect the Discover Groups / Domains option.
- Under the Node Discovery tab, deselect Lan Manager Systems and Active Directory Systems.
- Select DNS Names and IP Address.
- Under the System Discovery tab, select the Test Connection to system during discovery option.
- Under the IP Subnets tab, click Add.
- Add the appropriate Subnet Range by Class or CIDR Notation.
- Click Apply.
- Click Tasks > Run Manual Tasks > Run Discover Task.The IP subnet that has been configured are pinged and systems are discovered.