PRTG 9 Manual: Auto-Discovery

PRTG 9 Manual: Auto-Discovery

PRTG's auto-discovery function is a great way to automatically create a sophisticated and concise set of sensors for your complete network. It is mainly suitable for LAN discovery since it involves a lot of SNMP and WMI. For video instructions, please see the More section below.

For a quick start auto-discovery, please see TWO—Auto-Discover Your Network section.

How Auto-Discovery Works

PRTG's auto-discovery process has three stages:

Step 1
Scanning a network segment for devices using Ping (for groups only).
Step 2
Assessing the device type for all devices discovered in Step 1 (using SNMP, WMI and other protocols).
Step 3a
Creating sensor sets that match the discovered device types of step 2. This is done based on built-in device templates with recommended sensors for many device types.

Step 3b (optional)
Creating sensor sets using user created device templates (see Create Device Template section).

The auto-discovery can be used on a group level for a range of IP addresses, or for individual devices you might have created manually. It can be run just once, on demand via the context menu, or scheduled every hour, day or week. Running the auto-discovery every day or week will automatically create new sensors when new devices are connected to the network. As soon as new devices or sensors are discovered, new ToDos are created (which are usually mailed to the system administrator).

Please be aware of the following restrictions of the auto-discovery:

PRTG can not discover devices that can not be pinged, since Step 1 uses pings. If, for example, a firewall blocks echo requests, a device behind it cannot be discovered.
You should supply authentication settings for Windows Systems, Linux (SSH/WBEM) Systems, VMware/XEN Servers, and SNMP Devices in order to fully exploit the power of this feature. We recommend defining these in the Root group settings.
If a device has more than one IP address, it may show up more than once in the discovery results, even though PRTG tries to identify these situations.
If a device already exists on the same probe, the auto-discovery will skip this device and not create a duplicate.
Using frequent auto-discoveries of large network segments can lead to performance issues. We therefore recommend to only schedule regular auto-discoveries where necessary. For detailed information see the More section below.

Run Auto-Discovery Now

You can run an auto-discovery any time for a group or a device. To do so, right-click on the respective object and from the context menu, select Run Auto-Discovery. PRTG will immediately start searching for new objects it can add. If used for a group, PRTG will add devices and sensors, if found. If used for a device, it will add new sensors, if found.

Note: The auto-discovery will also re-add devices or sensors you have manually deleted. If you do not want this, please create objects manually only.

Creating an Auto-Discovery Group

There are several ways to start auto-discovery:

On the welcome screen, click on the Perform Network Auto-Discovery option
or select Devices | Add Auto-Discovery Group from the main menu.

To start an automatic detection of devices and sensors in your network. An assistant will appear, leading you through two steps. For faster setup, you can select Add Auto-Discovery Group... in the context menu of a probe or group to which you want to add the new group. This will skip step 1 and lead you directly to step 2.

Note: This documentation refers to the PRTG System Administrator user accessing the Ajax interface on a master node. For other user accounts, interfaces, or nodes, not all of the options might be available as described. When using a cluster installation, failover nodes are read-only by default.

Add Auto-Discovery Group Assistant Step 2

Step 1
Please choose a probe or group you want to add the new group to. Click on Continue.

Step 2
Add auto-discovery settings as described below.

Add Auto-Discovery Group Settings

Group Name and Tags
Group Name	Enter a meaningful name to identify the group. The name will be shown by default in the devices tree and in all alarms.
Tags	Enter one or more tags, separated by space or comma. You can use tags to group objects and use tag-filtered views later on. Tags are not case sensitive. We recommend using the default value. You can add additional tags to it, if you like. Tags are automatically inherited.

Group Type

Sensor Management

Select the method for automatic network discovery. Choose between:

Automatic device identification (standard, recommended): Detect mainly based on Ping, SNMP, and WMI. This option should work fine for most installations.
Automatic device identification (detailed, may create many sensors): Detect in a more detailed way and create more sensors. This option uses all standard device templates for auto-discovery. It is suitable for small network segments and whenever you want to monitor the maximum number of sensors available.
Automatic sensor creation using specific device template(s): Manually define the device templates used for auto-discovery. From the list below, select one or more templates.

Device Template(s)	This option is only available if using specific device templates is enabled above. Choose one or more device templates from the list by adding a check mark in front of the respective template name. Choose from: Cisco Device (Generic) DNS Server FTP Server Generic Device (PING only) Generic Device (SNMP-enabled) Generic Device (SNMP-enabled, Detailed) HTTP Web Server Hyper V Host Server Linux/UNIX Device (SNMP or SSH enabled) LocalhostRDP Mail Server (Generic) Mail Server (MS Exchange 2003) Mail Server (MS Exchange 2007) Misc. Details Printer (HP) Server (Compaq/HP agents) Switch (Cisco Catalyst) Switch (Cisco IOS Based) Switch (HP Procurve) UNIX/Linux Device UPS (APC) VMware ESX Server Windows (Detailed via WMI) Windows (via WMI) Windows IIS (via SNMP) XEN Server
Discovery Schedule	Define when the auto-discovery will be run. Choose between: Once: Perform auto-discovery only once. New devices and sensors will be added once. You can run auto-discovery manually any time using an object's context menu. Hourly: Perform auto-discovery for new devices and sensors every 60 minutes. Note: Please use this option with caution! Frequently executed auto-discoveries might cause performance issues, especially when large network segments are scanned every hour. Daily: Perform auto-discovery for new devices and sensors every 24 hours. The first auto-discovery will run immediately, all other discoveries will start on the time defined in the Auto-Discovery Settings section of the System Administration—System and Website settings. Weekly: Perform auto-discovery for new devices and sensors every 7 days. The first auto-discovery will run immediately, all other discoveries will start on the time defined in the Auto-Discovery Settings section of the System Administration—System and Website settings.
IP Selection Method	Define how you want to define the IP range for auto-discovery. Choose between: Class C base IP with start/end: Define a class C address range. List of individual IPs: Enter individual IP addresses. IP and subnet: Enter an IP address and subnet mask. IP with octet range: Enter an IP address range for every IP octet individually. With this, you can define very customizable IP ranges. Note: Only subnets with up to 65,536 IP addresses can be discovered! If you define a range with a higher number of addresses, discovery will stop before it is completed.
IP Base	This field is only visible if Class C network detection is selected above. Enter a class C network as IP base for the auto-discovery. Enter the first three octets of an IPv4 IP address, for example, 192.168.0
IP Range Start	This field is only visible if Class C network detection is selected above. Enter the IP octet of the class C network specified above from which PRTG will start the auto-discovery. This will complete the IP base above to an IPv4 address. For example, enter 1 to discover from 192.168.0.1.
IP Range End	This field is only visible if Class C network detection is selected above. Enter the IP octet of the class C network specified above at which PRTG will stop the auto-discovery. This will complete the IP base above to an IPv4 address. For example, enter 254 to discover up to 192.168.0.254.
IP List	This field is only visible if the IP list option is selected above. Enter a list of IP addresses which the auto-discovery will scan. Enter each address in a separate line.
IP and Subnet	This field is only visible if the IP and subnet option is selected above. Enter an expression in the format address/subnet, e.g. 192.168.3.0/255.255.255.0. You can also use the short form like 192.168.3.0/24 in this example. PRTG will scan the complete host range (without network and broadcast address) defined by the IP address and the subnet mask.
IP with Octet Range	This field is only visible if the octet range option is selected above. Enter an expression in the format a1.a2.a3.a4, where a1, a2, a3, and a4 are each a number between 0-255, or a range with two numbers and a hyphen like 1-127. All permutations of all ranges are calculated, e.g. 10.0.1-10.1-100 results in 1,000 addresses that PRTG will scan during auto-discovery.
Name Resolution	Define how newly discovered devices will be monitored. This only affects new devices. The setting for existing devices will be kept. Choose between: Use DNS / WMI / SNMP names (recommended): Monitor newly discovered devices via their DNS, WMI, or SNMP names (if available). Use IP addresses: Monitor newly discovered devices via their IP address. We recommend using the default value.
Device Rescan	Define if you want to rescan known devices. Choose between: Skip auto-discovery for known devices/IPs (recommended): Do not re-scan known devices or IP addresses, but only scan for new devices/IPs when auto-discovering. This can avoid re-creation of manually deleted sensors. PRTG will also avoid adding devices that are already included elsewhere in your configuration, e.g. in other groups. Perform auto-discovery for known devices/IPs: Re-scan known devices and IP addresses with every auto-discovery. This will re-create manually deleted sensors on existing devices. We recommend using the default value.

Inherited Settings

By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings. To change a setting for this object, disable inheritance by clicking on the check mark symbol in front of the respective setting name. You will then see the options described below.

If you have not set credentials yet, set them now before starting the auto-discovery in order to fully exploit the power of this feature!

Credentials for Windows Systems
Domain or Computer Name	Define the authority for Windows access. This is used for Windows Management Instrumentation (WMI) and other sensors. If using a Windows local user account, please enter the computer name here. If using a Windows domain user account, please enter the domain name here.
Username	Enter the username for Windows access. Usually, you will use credentials with administrator privileges.
Password	Enter the password for Windows access. Usually, you will use credentials with administrator privileges.

Credentials for Linux (SSH/WBEM) Systems
Username	Enter a login name for the Linux access via SSH and WBEM. Usually, you will use credentials with administrator privileges.
Login	Define which authentication method will be used for login. Choose between: Login via Password: Provide a password for login. Enter below. Login via Private Key: Provide a private key for authentication. Paste below.
Password	This field is only visible if password login is selected above. Enter a password for the Linux access via SSH and WBEM. Usually, you will use credentials with administrator privileges.
Private Key	This field is only visible if private key login is selected above. Paste a private key into the field. Usually, you will use credentials with administrator privileges. Note: If you do not insert a private key for the first time, but change the private key, you need to restart your PRTG core server service in order for the private key change to take effect!
For WBEM Use Protocol	Define the protocol that will be used for WBEM. This setting is only relevant when using WBEM sensors. Choose between: HTTP: Use an unencrypted connection for WBEM. HTTPS: Use an SSL-encrypted connection for WBEM.
For WBEM Use Port	Define the port that will be used for WBEM. This setting is only relevant when using WBEM sensors. Choose between: Set automatically (port 5988 or 5989): Use one of the standard ports, depending on whether unencrypted or encrypted connection is chosen above. Set manually: Use a custom port. Define below.
WBEM Port	This setting is only visible if manual port selection is enabled above. Enter the WBEM port number.

Credentials for VMware/XEN Servers
User	Enter a login name for access to VMware and XEN servers. Usually, you will use credentials with administrator privileges.
Password	Enter a password for access to VMware and XEN servers. Usually, you will use credentials with administrator privileges.
VMware Protocol	Choose between: HTTPS (recommended): Use an SSL-encrypted connection to VMware and XEN servers. HTTP: Use an unencrypted connection to VMware and XEN servers.

Credentials for SNMP Devices
SNMP Version	Select the SNMP version that will be used for device connection. Choose between: v1: Use the simple standard v1 protocol for SNMP connections. This protocol only offers clear-text data transmission, but it is usually supported by all devices. v2c: Use the more advanced v2c protocol for SNMP connections. Data is still transferred as clear-text, but it supports 64-bit counters. v3: Use the latest v3 protocol for SNMP connections. It provides secure authentication and data encryption. Note for SNMP v3: Due to internal limitations you can only monitor a limited number of sensors per second using SNMP v3. The limit is somewhere between 1 and 50 sensors per second (depending on the SNMP latency of your network). This means that using an interval of 60 seconds you are limited to between 60 and 3000 SNMP v3 sensors for each probe. If you experience an increased "Interval Delay" or "Open Requests" reading of the probe health sensor you need to distribute the load over multiple probes. SNMP v1 and v2 do not have this limitation.
Community String	This setting is only visible if SNMP version v1 or v2c are enabled above. Enter the community string of your devices. This is a kind of "clear-text password" used for simple authentication. We recommend using the default value.
Authentication Type	This setting is only visible if SNMP version v3 is enabled above. Choose between: MD5: Use Message-Digest Algorithm 5 (MD5) for authentication. SHA: Use Secure Hash Algorithm (SHA) for authentication. Your device must be set to the same value.
User	This setting is only visible if SNMP version v3 is enabled above. Enter a username for secure authentication. Your device must be set to the same value.
Password	This setting is only visible if SNMP version v3 is enabled above. Enter a password for secure authentication. Your device must be set to the same value.
Data Encryption Key (DES)	This setting is only visible if SNMP version v3 is enabled above. Enter a Data Encryption Standard (DES) key here. If you provide a key in this field, SNMP data packets will be enrypted using the DES encryption algorithm, providing increased security. Your device must be set to the same value. Note: If the key entered in this field does not match the key configured in the target SNMP device you will not get an error message! Please enter a string or leave the field empty.
SNMP Port	Enter the port used for SNMP communication. We recommend using the default value.
SNMP Timeout (sec.)	Enter a timeout in seconds for the request. If the reply takes longer than this value the request is aborted and an error message is triggered.

Click on the Continue button to store your settings. If you change tabs or use the main menu, all changes to the settings will be lost!

Auto-Discovery in Progress

While auto-discovery is running you may experience a lower system performance as usual, because PRTG works in the background in order to discover your network. Depending on the IP ranges defined (up to 65,536 addresses) , the discovery may run up to several days before complete. You can review the status of the discovery process as follows:

In the device tree, behind the group or device name, you will see a percentage value showing the progress of auto-discovery.
During auto-discovery, the web interface will display a box in the lower right corner, showing the number of active auto-discovery tasks.
In order to stop a running auto-discovery, right-click the group or device, and select Pause | For 5 minutes... from the context menu. Monitoring will be paused for 5 minutes, and auto-discovery tasks will be shut down.