Introduction
This series of articles is meant to help provide users guidance in using both Network Discovery and Agentless Inventory (also known as Inventory for Network Devices), and to provide details, processes, and tips to avoid issues and troubleshooting problems. In way of explanation, the engine that collects data for both Network Discovery and Agentless Inventory is the same engine. Before the technology was acquired by Symantec some time ago, the two products were one in the same. Many iterations later they are two distinct products, but Agentless does use the same engine for gathering data.
Network Discovery Dashboard
Note that Network Discovery must run successfully on a device using SNMP before an Agentless Inventory can be collected for that device. Without a Network Discovery, Agentless does nothing. Consider Agentless an SNMP extension of Network Discovery.
Additional NOTE! Network Discovery is first and foremost a network device inventory/discovery tool. While it is capable of finding computers, there are other methods that may be better suited for that purpose, such as an AD Import of computer objects, or the Domain Discovery provided by the Platform in relation to finding systems to install the Symantec Management Agent.
Network Discovery and Computers
An often hot topic in support is the way Network Discovery handles computer discovery. When used alongside Active Directory (AD) Import, Domain Discovery, and Symantec Management Agent installation, often duplicates can be created. These duplicates cause problems with reporting, target and filter management, and any aspect or picker in the Console where these duplicates may show up.
To combat duplication of computer records, consider the following:
- Avoid initial discovery of computers by Network Discovery.
- Run Network Discovery after the Symantec Management Agent has been installed.
- Clean up DNS so that Discovery gets the correct Name.Domain primary key. This primary key is the main way computers are identified uniquely in discovery circumstances, and how the Discovery engine matches found computers to existing records.
- Use AD Import or Domain Discovery instead of Network Discovery for the purpose of finding systems to install the Symantec Management Agent on.
- Do not use AD Import or Domain Discovery if Network Discovery is meeting your needs. The three different discovery methods are redundant in a lot of cases so it may be best to choose one of the three to use.
- Delete duplicates after a Network Discovery if the situation cannot be avoided.
Not all of these items are doable depending on the circumstances. Network Discovery has in recent years helped the duplicate issue by reevaluating the items used to identify unique machines already registered in the Symantec Management Platform.
The following process is used when looking up existing systems within the Symantec CMDB Database.
There are 2 primary keys used by Network Discovery in order to avoid creating duplicates and instead updating existing records in the database. These keys are:
- NetBios Name, Domain (name.domain key)
- MAC Address
This comparison is done against the results from the stored procedure tmBuildTargetDeviceCache which uses the vTaskTargetDevices view which obtains MAC addresses from the Inv_AeX_AC_TCPIP table. This table is populated by the Symantec Management Agent as part of Basic Inventory, or is populated by Stand-alone Inventory, AD Import, or Domain Discovery. Most discovery or agent inventory pieces contain this data class.
vTaskTargetDevices View
Note: vTaskTargetDevices returns information about only one NIC for each computer. So relevant information may be ignored for computers with multiple NICs. While certain dummy NICs are ignored (those with IP addresses 0.0.0.0 or 127.0.0.1). Of the remaining NICs, the NIC about which information is returned is arbitrarily selected. So a different NIC may be returned by vTaskTargetDevices each time it is run.
With Network Discovery using ICMP or SNMP, Network Discovery creates and/or modifies the following resource keys
- hostname = CL-XP-01
- nbname.domain = CL-XP-01.EPM
- macaddress = 00-50-56-05-41-76
Additionally Network Discovery creates and/or modifies the Fully Qualified Doain Name (FQDN) resource key with the devices short name, for example:
- fqdn = CL-XP-01
Whereas the Altiris agent also creates and/or modifies the FQDN resource key with a longer name, for example:
- fqdn = CL-XP-01.EPM.LOCAL
Note: This discrepancy causes the resource key to alternate between these two values. I am not aware of any adverse effects of this discrepancy.
Thus if the MAC address or netbiosname.domain values do not match up, a duplicate will be created.
Further articles will cover more about Troubleshooting to understand how to troubleshoot duplicate issues. Another article on the Discovery Engine will be provided to see how Network Discovery is finding and capturing data on computers.
Next Article:
Network Discovery and Inventory for Network Devices Tips and Tricks Article 2