Configuring discovery settings
You can configure Discovery settings by using the Discovery Settings page.
To configure Discovery settings
- From the main menu, click the Administration icon. The Administration page opens.
- In the Discovery section, click an icon corresponding to the settings you want to configure.
The following icons are described in more in-depth topics:
- Platforms - see Managing the discovery platform scripts
- SNMP Devices - see Supported SNMP devices
- Storage Devices - see Viewing storage
- Sensitive Data Filters - see Masking sensitive data
- Event Sources - see Event driven model updates
- Make any required changes to the settings on the page and click Apply.
- To cancel any of your changes, click Reset To Defaults.
Ports
This section contains settings related to the ports that BMC Helix Discovery uses.
Field Name | Details |
|---|---|
TCP ports to use for initial scan | Enter the TCP ports that will be scanned on a first scan. Use this setting to prevent scanning of any ports that you want to avoid. |
UDP ports to use for initial scan | Enter the UDP ports that will be scanned on a first scan. Use this setting to prevent scanning of any ports that you want to avoid. The default is port 161. |
SSH ports | The default is port 22. Enter any custom ports to scan in a comma-separated list in the Change To column. |
RLogin ports | Only the default port 513 is supported so must be empty or 513. |
Windows ports | Only the default port 135 is supported so must be empty or 135. |
Telnet ports | The default is port 23. Enter any custom ports to scan in a comma-separated list in the Change To column. |
FTP ports | The default is port 21. Enter any custom ports to scan in a comma-separated list in the Change To column. |
SNMP ports | The default is port 161. Enter any custom ports to scan in a comma-separated list in the Change To column. |
HTTP ports | The default is port 80. Enter any custom ports to scan in a comma-separated list in the Change To column. |
HTTPS ports | The default is port 443. Enter any custom ports to scan in a comma-separated list in the Change To column. |
VMware Authentication Daemon ports | Only the default port 902 is supported so must be empty or 902. |
Mainframe z/OS Agent ports | The default is port 3940. Enter any custom ports to scan in a comma-separated list in the Change To column. |
WBEM HTTP ports | The default is port 5988. Enter any custom ports to scan in a comma-separated list in the Change To column. |
WBEM HTTPS ports | The default is port 5989. Enter any custom ports to scan in a comma-separated list in the Change To column. |
| PowerShell HTTP ports | The default is port 5985. Enter any custom ports to scan in a comma-separated list in the Change To column. |
| PowerShell HTTPS ports | The default is port 5986. Enter any custom ports to scan in a comma-separated list in the Change To column. |
Valid Port States | When nmap runs port scans, it returns a result of open, closed, or filtered. Using the check boxes, you can choose which states are valid to investigate further. |
Check port 135 before using Windows access methods | On Windows computers, port 135 is usually open. Selecting Yes for this option means that nmap checks whether port 135 is open before a Windows proxy is used to discover an IP device. The default is open. |
Device identification
This section contains settings related to the methods that discovery uses to identify devices.
Field Name | Details |
|---|---|
Use last login method | Discovery uses the discovery method recorded as having been used successfully for an IP address. |
Use SNMP SysDescr to identify OS | Discovery attempts to query the host's SNMP service for the SysDescr value to determine the OS. |
Always try "public" SNMP community when using SNMP to identify OS | Discovery attempts to use the public SNMP community to query the host's SNMP service if no credential is available for that host. In this case, only device classification is possible. |
Use Mainframe z/OS Agent to identify mainframes | Discovery attempts to connect to the z/OS Agent to determine whether the discovery target is a mainframe computer. |
Use Telnet banner to identify OS | Discovery makes a Telnet connection to a host and uses the Telnet "welcome" banner to determine host and OS information. |
Use HTTP(S) HEAD request to identify OS | Discovery attempts to connect to port 80 or 443 of the host and perform an HTTP or HTTPS HEAD request to determine the host and OS. |
Use FTP banner to identify OS | Discovery starts an FTP session with the host and uses the FTP "welcome" banner to determine host and OS information. |
Use vSphere API to identify OS | Discovery makes a TCP connection to examine the header and ensure that the VMware authentication daemon is really on port 902 (or the specified port). When confirmed, Discovery makes a webservices request. This type of request requires an open VMware authentication daemon and HTTPS port, and a valid vSphere credential. |
| Use WBEM queries to identify Storage devices | Discovery attempts WBEM queries to determine whether the discovery target is a storage device. |
| Use Web API queries to identify devices | Discovery attempts Web API queries to try and determine the type of device. |
| Use REST API queries to identify devices | Discovery attempts WBEM queries to try and determine the type of device. |
Use IP Fingerprinting to identify OS | This option controls whether discovery will use IP fingerprinting to determine the OS if previous methods have been unsuccessful. You can configure the network ports scanned during this phase of discovery. The process of IP fingerprinting can cause instability in some legacy systems and might trigger intrusion detection systems. This option is enabled by default. |
Use open ports to identify OS | This option controls whether open ports are used to identify the OS. |
Discovery Sessions
This section contains settings related to the way in which discovery uses sessions to log in and run commands.Field Name | Details |
|---|---|
Session line delay | A delay of 10 ms is introduced between each line sent by Discovery. This avoids problems where remote shells are unable to cope with rapid command sequences. Select one of the following from the list: 1, 2, 5, 10 (the default), 15, 20, 25, 50, 100 milliseconds. |
Session login timeout | The length of time for the discovery script to wait for a login prompt. If the timeout is exceeded, the attempt is abandoned. |
Maximum search window size | The amount of data to examine when detecting the shell command prompt. The default value is 512 bytes. Warning: Changing the default value may cause significant degradation of appliance performance. Do not change this value unless directed by Customer Support. |
Authorised prompt | Certain systems require an authorization step after login. At the command line, you are prompted to enter session details. The required response is usually a user name and some other information. |
Authorised response | Where an Authorised Prompt has been entered, you must enter the expected response (that you would enter at the command line) in the Authorised Response field. |
Scanning
This section contains settings related to any scanning that discovery undertakes.
Field Name | Details |
|---|---|
| Allowable IP Ranges | Enter the IP ranges that the appliance is permitted to scan. You should set the Allowable IP Ranges, Excluded IP Ranges, and Scope settings as a group to ensure that the appliance only scans the required IP addresses, and where appropriate applies a scope to the IP addresses. See Overlapping IP addresses for more information. |
| Excluded IP Ranges | Enter the IP ranges that the appliance is not permitted to scan. You should set the Allowable IP Ranges, Excluded IP Ranges, and Scope settings as a group to ensure that the appliance only scans the required IP addresses, and where appropriate applies a scope to the IP addresses. See Overlapping IP addresses for more information. |
| Scope | Scope distinguishes between endpoints in different address spaces. You should avoid scanning the same endpoint using appliances or BMC Discovery Outposts in different scopes, otherwise, you will have duplicates for that endpoint. See Overlapping IP addresses for more information. Enter the scope that this appliance will apply to IP addresses to distinguish between overlapping address spaces. The default scope is You should set the Allowable IP Ranges, Excluded IP Ranges, and Scope settings as a group to ensure that the appliance only scans the required IP addresses, and where appropriate applies a scope to the IP addresses. |
| Scope mode | BMC Helix Discovery provides a scope transition mode that can be used when first using a scope. The scope transition mode is useful in any system with existing data, where scopes have been added, and particularly in upgraded systems. In transition mode, if a device is scanned in a scope and no existing device node is found, the system looks for a matching device in the default scope, and if one is found, it is updated, including the addition of the scope. When you upgrade and choose to use scope, you should set the appliance to use transition mode until you have scanned the endpoints covered by the BMC Discovery Outposts or appliances where the scope has been configured. If you do not use the scope transition mode, you will see duplication of devices discovered at those endpoints, though the ones without scope will age out as normal. Select either: Full scope mode In normal operation, Full scope mode should be set. Full scope mode is the default setting. |
Ping before scanning | If this option is disabled, then all hosts are discovered, but the discovery of empty IP address ranges will be slower. The default is to allow discovery to ping the host first. |
Use TCP ACK 'ping' before scanning | Ping addresses with TCP ACK packets to determine which hosts are actually up. Use this option when scanning networks that do not permit ping packets. You can specify multiple ports in a comma-separated list. |
Use TCP SYN 'ping' before scanning | Ping addresses with TCP SYN packets to determine which hosts are actually up. Use this option when scanning networks that do not permit ping packets. You can specify multiple ports in a comma-separated list. |
Exclude ranges from ping | Enter a list of IP addresses or IP address ranges that you do not want to ping. For example, you might want to scan IP addresses that are behind a firewall that blocks ICMP packets. If BMC Discovery pings an IP address and receives no response, it makes no further attempt to scan that IP address. Excluding a range from pinging enables you to scan IP addresses behind such firewalls. |
Scan retries | Number of retries to be attempted on each host. The system will retry only for machines on which the OS cannot be determined. |
Scan timeout | Timeout (in minutes) that applies when BMC Discovery uses nmap to determine open ports or performs OS fingerprinting. Scan timeout is not used to limit the time to scan devices. See also the credential timeout for the sessions. |
Minimum time before end of window to avoid starting new scheduled discovery operations | A discovery run can take some time to complete. If it is started too close to the end of a Discovery window, it does not finish before the end of the window. To prevent this issue, you can specify a period in which discovery runs are not started. The default is 30 minutes, meaning that no discovery runs are started within 30 minutes of the end of a discovery window. Select the period from the following values in the list: 5, 10, 15, 20, 25, 30, 35, 40, and 45 minutes. |
Discover Desktop Hosts | Use this option to permit or prevent the discovery of desktop hosts. The default is No; that is, do not discover desktop hosts. When this option is set to No, if a Windows or Mac OS host is determined to be the desktop, the host is skipped. An SMB query is used to determine whether the endpoint is a Windows desktop. See Dark space scans for more information. When a host is skipped, the device_type attribute on the Device Info node is set to Desktop, no inferred host is created, and the corresponding DiscoveryAccess result is shown as "Skipped (Desktop host discovery has been disabled)." |
Discover neighbor information when scanning network devices | Causes discovery to retrieve MAC and port information from neighboring scanned network devices. The default is Yes. Select No only if you do not want to collect any edge connectivity information. |
| Restore Scan Status | If enabled, scanning is enabled and you have a vault with either no passphrase or a saved passphrase the system will restart scanning when services are restarted. In all other cases restarting services will result in scanning being disabled. |
Implicit scans | |
Maximum concurrent requests against vCenter | The maximum number of concurrent requests that will be made against individual vCenter servers. Select the maximum number from the following values in the list: 1, 3, 5,7, 10, 15, 20 (the default), 25, and 30. |
Other Settings
This section contains other discovery settings.
Field Name | Details |
|---|---|
Recording mode | Record and playback modes are intended for diagnostic support and testing. Select one of the following discovery modes from the list: |
Maximum concurrent discovery requests per engine | Specifies the maximum number of concurrent discovery requests permitted per processing engine. The maximum value and available range of settings are calculated for optimum performance depending on the appliance. Values shown in the list depend on the number of processing engines. The base values in the list are 30 (default), 60, 90, 120, and 150. If you change this option, you must restart scanning for the changes to take effect. Leave this setting at its default unless you have many discovery commands timing out. As a general rule, for more discovery requests permitted concurrently, you increase network traffic, and the absolute time for discovering a single host increases. However, total throughput might be improved with the interleaving of discovery processing. |
Trade discovery performance with interactivity | Scanning IP addresses, consolidation, and manual pattern execution can place a heavy load on the system. During such times, the UI can become unresponsive. You can choose to delay these tasks to provide additional resources for the UI. Doing so provides better interactivity with the system, but at a cost in raw discovery performance. You can choose from the following options: If you change this option, you must restart scanning for the changes to take effect. |
Enable Automatic Grouping | Automatic grouping is the automatic grouping of hosts into logical groups called Automatic Groups. This is primarily intended to help in baselining. By default, it is enabled. Select this option to enable Automatic Grouping. Disabling Automatic Grouping might improve scanning performance. |
Implicit Scans
This section contains settings related to implicit scans
Field Name | Details |
|---|---|
Maximum concurrent requests against vCenter | The maximum number of concurrent requests that will be made against individual vCenter servers. Select the maximum number from the following values in the list: 1, 3, 5,7, 10, 15, 20 (the default), 25, and 30. |
| Maximum number of AWS Systems Manager Session requests | Maximum number of concurrently active AWS Systems Manager Sessions permitted each second, for each account, for each region. AWS imposes a limit on this, and if you raise the value, you might encounter dropped connections and reduced performance. |
| Maximum concurrently active AWS Systems Manager Sessions | Maximum number of concurrently active AWS Systems Manager Sessions, for each account, for each region. AWS imposes a limit on this, and if you raise the value, you might encounter dropped connections and reduced performance. |
Scanning and data processing levels
The Discovery Engine and the Reasoning Engine (collectively the discovery process) cooperate to:
- Scan selected ranges
- Process data
- Create a detailed data model
The data model defines all discovered objects and the relationships between them and is defined in the system taxonomy.
The processing that the discovery process uses to create this complex, detailed, and interrelated data model is considerable. You can control the level of processing used, and consequently the accuracy, complexity, and detail in the data model, giving performance benefits at the cost of model accuracy. You might find that by reducing the level of processing used, you speed the rollout of BMC Discovery throughout your organization.
The following levels are available:
- Sweep Scan—Performs a sweep scan, trying to determine what is at each endpoint in the scan range. Sweep scan attempts to log in to a device to determine the device type.
- Full Discovery—Retrieves all the default information for hosts, and complete full inference.
Order of operations
Where selected, these groups of operations are carried out in the following order:
- Ping hosts before scanning
- Use TCP ACK "ping" before scanning
- Use TCP SYN "ping" before scanning
- TCP ports to use for initial scan
- UDP ports to use for initial scan
- Use IP Fingerprinting to Identify OS
TCP and UDP ports to use for initial scan
The initial port scan is an important part of discovery. If you remove a port from the initial port scan, that port is effectively removed from discovery. For example, if you remove port 22, you will effectively disable SSH access.
The Use Last Login settings override any settings made in ports for use for initial scan. For example, if you disable port 23 using this feature, but a host has previously been discovered using Telnet, this host is still discovered using Telnet, because it is listed as the last login for the host.
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