This page provides the following topics:
- Scan Configuration
- Configuring the Scan
- Process for Network Discovery
- Avoiding Issues with Network Discovery
Scan Configuration
After you install Onsite Manager, the first scan runs automatically, without the need to manually configure the settings. However, you may want to change the scan range and frequency values set for device and asset discovery. See Setting the Device Discovery Defaults.
Configuring the Scan
You can configure the scan by:
- Adding individual IP addresses, ranges of IP addresses, IP subnets or any combination of these.
- Skipping individual IP addresses or ranges of IP addresses.
- Excluding devices from the scan.
- Deleting individual IP addresses, ranges of IP addresses, IP subnets or any combination of these that have been previously configured.
Process for Network Discovery
Onsite Manager queries each IP address defined in the network scan using an ICMP ECHO request. An ARP cache retrieval is also performed to detect IP addresses on the local subnet that may not respond to the ICMP ECHO request. Each IP address that responds is further scanned to determine its identity.
To identify | Onsite Manager |
---|---|
A-name | Queries the reverse lookup zone in DNS and then validates with the forward lookup zone. |
Machine name | Uses WMI calls. |
sysName | Uses SNMP calls. |
MAC addresses | Uses WMI or SNMP calls. |
Onsite Manager uses a combination of device protocols to identify devices, including:
- SSH
- Zeroconf
- NetBIOS
All the collected identifying factors are used to create discovery variables, which are then compared against each known device to see if a match can be found. If a match is found, the IP address is associated with the known device. If no match is found, a new device is created.
Avoiding Issues with Network Discovery
Any or all the following actions help Onsite Manager classify unique devices and avoid issues with network discovery:
- Enable a management protocol (such as WMI, SNMP, or SSH) on each device.
- Assign static IP addresses to devices that do not have a management protocol enabled.
- Assign unambiguous DNS names to the device so that it is uniquely reverse resolvable.
Scanning remote locations (over VPN, MPLS, and other similar configurations) is not recommended because it results in less efficient scans that take more time. A separate Onsite Manager is recommended for each physical location.