Defining Group Data Collection Settings

Group data collection settings (Settings icon > Setup > Collection and Groups) settings define global NetMRI settings for discovery and configuration management:

• Polling networks during the discovery process and collecting configuration files from network devices.
• Editing group rankings, adding or deleting groups.
• Setting groups' discovery data collection settings.

Global tab settings in the Network Polling panel (Settings icon > Setup > Collection and Groups > Global tab > Network Polling side tab) provide system-level control over NetMRI's SNMP and discovery data collection operations.

• Port Scanning: If enabled, NetMRI probes the TCP and UDP ports listed at Settings icon > Setup > Port List, to determine whether they are open. See the results of this scanning action at Network Explorer > Summaries > Ports for the entire network, and Device Viewer > Device/Network Explorer > Open Services for an individual network device.
  If Port Scanning is disabled, NetMRI attempts no port probes other than SNMP on any device. 

• Fingerprinting: (Available in full NetMRI license) If enabled, NetMRI attempts to identify each network device based on the response characteristics of its TCP stack. This information is used to determine the device type. In the absence of SNMP access, fingerprinting is usually the only way to identify non-network devices. If disabled, devices accessible via SNMP are identified correctly; all other devices are assigned a device type of Unknown.
  Fingerprinting is disabled by default for network polling. You must enable fingerprinting to use the Automation Change Manager's Rogue DHCP Detection feature. If you enable Configuration Collection (see below), NetMRI attempts Telnet and SSH access only on network devices.

• SNMP Collection: If enabled, all data collectors start after this page is saved. If you disable SNMP collection in this tab (i.e., globally), data already collected by NetMRI remains available for viewing; no new data is added and no existing data is removed; this also disables group and device SNMP collection.
  SNMP Collection is disabled, for example, when NetMRI is used for offline assessments. By disabling SNMP Collection before removing NetMRI from the network, data can be examined later without any data expiring. SNMP collection can also be enabled/disabled for groups and devices.
• Performance Collection: If enabled, performance data such as CPU and memory statistics are collected.
• Use Vendor Community Strings: If enabled, NetMRI uses vendor default community strings when determining a device's community string. If disabled, NetMRI uses community strings with an Origination of User.
• NetBIOS Scanning: Global setting to enable NetMRI to collect the NetBIOS name for endpoint devices in the network. Device groups also enable NetBIOS scanning. The device group setting is dependent on the global setting; without enabling the NetBIOS Scanning checkbox, scanning at the device group will not take place. This feature can be enabled only by users with SysAdmin privileges. This feature is globally disabled by default (and also for device groups) to prevent unexpected scanning of the network by a new collector.
• Smart Subnet Ping Sweep (IPv4 only): Checkbox to enable subnet Ping sweeps on IPv4 networks, using a range of packets to detect the presence of a system on each IP in the specified range, using ports that are generally open across the network. Performs probes across ICMP Echo, ICMP Timestamp, TCP SYN to port 80, and TCP SYN to port 443. Subnet ping sweeps are used as a last resort in the discovery process. A subnet ping sweep is performed if NetMRI is unable to identify any network devices in a given subnet. Subnet ping sweeps are performed no more than once per day and will stop on a given subnet once NetMRI discovers a network device and is able to collect data.
  Smart Subnet ping sweep is most useful for the complete discovery of end-host network segments. Ping sweeps are a tool to aid in discovery, but most discovery operations take place through ARP tables and routing tables collected from infrastructure devices. Avoid using ping sweeps on a large number of discovery ranges, or discovery ranges that are too large (more than a /22 in size) as devices discovered through this method may expire from NetMRI's database before they are refreshed by another discovery cycle. Smart subnet ping sweeps should not be attempted on subnets larger than /22. Ping sweeps are not used on IPv6 networks because of the dramatically greater scale of network addresses in the IPv6 realm. Smart subnet ping sweeps also have several differences from the discovery ping sweeps that can be enabled under Discovery Settings, which can be found under Settings icon > Setup > Discovery Settings.

• Refresh device caches before collecting switch port data: Checkbox to enable refreshing of ARP caches on switches and switch-routers in the managed network before NetMRI performs polling of switch ports. Enabling this feature will not produce an automatic ping sweep of the managed network. The benefit of this feature is that it enables more accurate detection of all endpoint devices on switches. Without ARP refresh, some endpoint devices may not be detected. This feature is globally disabled by default. With this setting globally enabled, individual device groups can also be set to enable or disable this feature. For more information, see Global Switch Port Management Polling Settings
• ARP Collection Priority: (Available in full NetMRI license) Defines the collection method for collecting ARP databases from devices. When set to CLI with SNMP Fallback, NetMRI collects ARP data from devices with the CLI when NetMRI has the appropriate access credentials for the active network device. This mode of collection works only for Cisco devices and will fall back to SNMP if CLI access does not work. SNMP data collection is used for active devices from all other vendors.
• Route Collection Priority: (Available in full NetMRI product license) This setting controls which collection method is attempted first when collecting route tables. Should the Route Collection Priority setting be set to SNMP (default), you will also need to pay attention to the Route Limit setting under Advanced Settings (see NetMRI Advanced Settings). If NetMRI encounters a routing table with a table of entries beyond the Route Limit setting, SNMP collection for the current device will be stopped, and CLI collection for the routing table will be tried instead. When set to CLI with SNMP Fallback, NetMRI will try to use CLI commands to collect route tables from devices instead of immediately using SNMP. The CLI option may reduce data collection performance problems for routers with large route tables.