# "SCCM Planning-Resource Discovery
Resource discovery
This article mainly discusses the resource discovery methods and matters needing attention in ConfigMgr. For ConfigMgr, Active Directory forest, group, user, computer object, client heartbeat data and so on all belong to ConfigMgr resources.
DDR
ConfigMgr creates its corresponding DDR (data discovery record) file based on the discovered object. When the site server detects the DDR file, it automatically reads the DDR file and inserts the corresponding information into the ConfigMgr database.
Discovery method
ConfigMgr supports the following types of resource discovery:
By default, ConfigMgr uses the site server computer account for discovery operations
Active Directory forest discovery: used to discover Active Directory forest and its site information
Active Directory group discovery: discovery of Active Directory group, membership
Active Directory user Discovery: discover Active Directory user object and its LDAP attribute
Active Directory system Discovery: discovery of Active Directory computer objects
Heartbeat discovery: not for discovering new resources, but for tracking and maintaining client computer information
Network Discovery: search Domain, SNMP, DHCP to find resources, such as computers, printers, routers, IP subnets and other resources; supplementary information
Active Directory Forest Discovery automatically creates discovered Active Directory sites as ConfigMgr boundary objects
Active Directory group discovery can discover security group and distribution group objects and their membership. For security group objects, they will further discover the computer and user objects under them.
The Active Directory system found that a DDR file will be created for an object only after the site server can successfully resolve the DNS name of the object to an IP address.
Heartbeat discovery also generates a DDR file that contains the following information: is the client installed? Information such as client type, client version, Netbios name, etc
Network discovery validates the destination subnet mask (subnet mask) through router ARP cache, DHCP server (must be Windows server), and SNMP device
Network discovery can limit the range of devices that SNMP and DHCP can discover through subnets, and additional router hops can be set for SNMP to limit the range of discovery; manually import device information
ConfigMgr also supports manually adding devices to the ConfigMgr level, and you must specify how to information when importing:
Device name device Mac address or device SMBIOS GUID
It is the original intention of this series of articles to refine the basic knowledge, precautions, operating mechanism and troubleshooting methods involved in SCCM for readers. There are already many articles in the network to refer to the information on the various components and functional deployment steps of SCCM, so this series of articles do not focus on providing deployment guides similar to Step-by-Step, please forgive me. At the same time, due to the limitations of personal ability and knowledge, there are inevitably some mistakes and mistakes in the article. I hope you can correct them. Thank you very much.
