<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: Cloud HTTP Sensor

The Cloud HTTP sensor monitors the loading time of a web server via HTTP from different locations worldwide using the PRTG Cloud. The locations are distributed among three continents around the globe.

The sensor can show the response time and response code of the target server monitored from the following locations:

  • Asia Pacific: Singapore
  • Asia Pacific: Sydney
  • Asia Pacific: Tokyo
  • EU Central: Frankfurt
  • EU West: Ireland
  • South America: São Paulo
  • US East: Northern Virginia
  • US West: Northern California
  • US West: Oregon
  • Global average response time
Cloud HTTP Sensor

Cloud HTTP Sensor

Sensor in Other Languages

Dutch: Cloud HTTP, French: Cloud HTTP, German: Cloud HTTP, Japanese: クラウド HTTP, Portuguese: Cloud HTTP, Russian: Облако HTTP, Simplified Chinese: 云 HTTP, Spanish: Http de nube

Remarks

  • The server on which the probe with this sensor runs must have access to the internet. The probe system needs to be able to reach https://api.prtgcloud.com:443 to communicate with the PRTG Cloud.
  • The address you define in the settings of the parent device must be reachable over the internet. You cannot use this sensor to monitor localhost (127.0.0.1) or other target devices that are only reachable within your private network.
  • This sensor inherits Proxy Settings for HTTP Sensors from the parent device.
  • This sensor has predefined limits for several metrics. You can individually change these limits in the channel settings. For detailed information about channel limits, see section Sensor Channel Settings.
  • This sensor supports smart URL replacement.
  • This sensor uses lookups to determine the status values of one or more sensor channels. This means that possible states are defined in a lookup file. You can change the behavior of a channel by editing the lookup file that the channel uses. For details, see section Define Lookups.
  • In rare cases, this sensor may result in false timeouts and show the error message The returned JSON does not match the expected structure (Invalid JSON.). (code: PE231). In this case, set the If a Sensor Query Fails option to up to five scanning intervals to not receive false alerts.

Add Sensor

The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the setting fields that are required for creating the sensor. Therefore, you do not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.

Sensor Settings

On the details page of a sensor, click the Settings tab to change its settings.

icon-i-roundUsually, a sensor connects to the IP Address or DNS Name of the parent device on which you created the sensor. See the Device Settings for details. For some sensors, you can explicitly define the monitoring target in the sensor settings. See below for details on available settings.

Basic Sensor Settings

Sensor Name

Enter a meaningful name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets.

Parent Tags

Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here.

Tags

Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value.

There are default tags that are automatically predefined in a sensor's settings when you add a sensor. See section Default Tags below.

You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.

icon-i-roundIt is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with parentheses (()) or angle brackets (<>).

Priority

Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. A sensor with a top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority).

Default Tags

httpsensor

HTTP Settings

URL

Enter the URL that the sensor connects to. It has to be URL encoded. If you enter an absolute URL, the sensor uses this address independently from the IP address/DNS name setting of the device on which you create this sensor. You can enter an URL leading to a web page (to measure the page source code's loading time), or enter the URL of an image or of another page asset to measure this element's availability and loading time.

PRTG uses a smart URL replacement that lets you use the parent device's IP address or Domain Name System (DNS) name setting as part of the URL.

icon-book-arrowsFor more information, see section Smart URL Replacement below.

Request Method

Select an HTTP request method to determine how the sensor requests the specified URL:

  • GET: Directly request the website, like browsing the web. We recommend that you use this setting for a simple check of a web page.
  • POST: Send post form data to the URL. If you select this setting, you must enter the data that is sent in the Postdata field below.
  • HEAD: Only request the HTTP header from the server without the actual web page. Although this saves bandwidth because less data is transferred, it is not recommended because the measured request time is not the one experienced by your users and you might not be notified of slow results or timeouts.

Postdata

This field is only visible if you select POST as Request Method setting above. Enter the data part for the POST request.

icon-i-round-redNo Extensible Markup Language (XML) is allowed here!

icon-i-blueOnly the content type application/x-www-form-urlencoded is supported.

Timeout (Sec.)

Enter a timeout in seconds for the server request. If the reply takes longer than this value defines, PRTG cancels the request and shows an error message. The maximum timeout value is 5 seconds.

Sensor Display

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel is always displayed below the sensor's name. The available options depend on what channels are available for this sensor.

icon-i-roundYou can set a different primary channel later by clicking the pin symbol of a channel on the sensor's Overview tab.

Graph Type

Define how different channels are shown for this sensor:

  • Show channels independently (default): Show a graph for each channel.
  • Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This generates a graph that visualizes the different components of your total traffic.
    icon-i-roundThis option cannot be used in combination with manual Vertical Axis Scaling (available in the Sensor Channel Settings settings).

Stack Unit

This field is only visible if you enable Stack channels on top of each other as Graph Type. Select a unit from the list. All channels with this unit are stacked on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Inherited Settings

By default, all of the following settings are inherited from objects that are 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. For more information, see section Inheritance of Settings. To change a setting for this object only, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You then see the options described below.

Scanning Interval

Click inherited_settings_button to interrupt the inheritance. See section Inheritance of Settings for more information.

Scanning Interval

Select a scanning interval (seconds, minutes, or hours). The scanning interval determines the amount of time that the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations.

If a Sensor Query Fails

Define the number of scanning intervals that the sensor has time to reach and check a device again in case a sensor query fails. Depending on the option that you select, the sensor can try to reach and check a device again several times before the sensor shows a Down status. This can avoid false alarms if the monitored device only has temporary issues. For previous scanning intervals with failed requests, the sensor shows a Warning status. Choose from:

  • Set sensor to down immediately: Set the sensor to a Down status immediately after the first failed request.
  • Set sensor to warning for 1 interval, then set to down (recommended): Set the sensor to a Warning status after the first failed request. If the following request also fails, the sensor shows an error.
  • Set sensor to warning for 2 intervals, then set to down: Set the sensor to a Down status only after three consecutively failed requests.
  • Set sensor to warning for 3 intervals, then set to down: Set the sensor to a Down status only after four consecutively failed requests.
  • Set sensor to warning for 4 intervals, then set to down: Set the sensor to a Down status only after five consecutively failed requests.
  • Set sensor to warning for 5 intervals, then set to down: Set the sensor to a Down status only after six consecutively failed requests.

icon-i-roundSensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval before they show a Down status. It is not possible to immediately set a WMI sensor to a Down status, so the first option does not apply to these sensors. All other options can apply.

icon-i-roundIf you define error limits for a sensor's channels, the sensor immediately shows a Down status. No "wait" option applies.

icon-i-roundIf a channel uses lookup values, the sensor immediately shows a Down status. No "wait" options apply.

icon-i-roundThis sensor has a fixed minimum scanning interval for performance reasons. You cannot run the sensor in shorter intervals than this minimum interval. Consequently, shorter scanning intervals as defined in System Administration—Monitoring are not available for this sensor.

For Cloud HTTP sensors, the minimum scanning interval is 10 minutes.

Schedules, Dependencies, and Maintenance Window

icon-i-roundYou cannot interrupt the inheritance for schedules, dependencies, and maintenance windows. The corresponding settings from the parent objects are always active. However, you can define additional settings here. They are active at the same time as the parent objects' settings.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days or hours) every week.

icon-book-arrowsYou can create schedules, edit schedules, or pause monitoring for a specific time span. For more information, see section Account Settings—Schedules.

icon-i-roundSchedules are generally inherited. New schedules are added to existing schedules, so all schedules are active at the same time.

Maintenance Window

Specify if you want to set up a one-time maintenance window. During a maintenance window, the current object and all child objects are not monitored. They are in a Paused status instead. Choose between:

  • Not set (monitor continuously): No maintenance window is set and monitoring is always active.
  • Set up a one-time maintenance window: Pause monitoring within a maintenance window. You can define a time span for a monitoring pause below and change it even for a currently running maintenance window.

icon-i-roundTo terminate a current maintenance window before the defined end date, change the time entry in Maintenance Ends to a date in the past.

Maintenance Begins

This field is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the start date and time of the maintenance window.

Maintenance Ends

This field is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the end date and time of the maintenance window.

Dependency Type

Define a dependency type. You can use dependencies to pause monitoring for an object depending on the status of another object. You can choose from:

  • Use parent: Use the dependency type of the parent object.
  • Select a sensor: Use the dependency type of the parent object. Additionally, pause the current object if another specific sensor is in a Down status or in a Paused status caused by another dependency.
  • Master sensor for parent: Make this sensor the master object for its parent device. The sensor influences the behavior of its parent device: If the sensor is in a Down status, the device is paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor is paused if the parent group is paused by another dependency.

icon-i-roundTo test your dependencies, select Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later, all dependent objects are paused. You can check all dependencies under Devices | Dependencies in the main menu bar.

Dependency

This field is only visible if you enable Select a sensor above. Click the Search button and use the object selector to select a sensor on which the current object will depend.

Dependency Delay (Sec.)

This field is only visible if you enable Select a sensor above. Define a time span in seconds for dependency delay.

After the master sensor for this dependency comes back to an Up status, monitoring of the dependent objects is additionally delayed by the defined time span. This can help avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Enter an integer value.

icon-i-round-redThis setting is not available if you set this sensor to Use parent or to be the Master sensor for parent. In this case, define delays in the parent Device Settings or in its parent Group Settings.

Access Rights

Click inherited_settings_button to interrupt the inheritance. See section Inheritance of Settings for more information.

User Group Access

Define the user groups that have access to the selected object. A table with user groups and types of access rights is shown. It contains all user groups from your setup. For each user group, you can choose from the following access rights:

  • Inherited: Use the access rights settings of the parent object.
  • None: Users in this group cannot see or edit the object. The object neither shows up in lists nor in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree but it cannot be accessed.
  • Read: Users in this group can see the object and review its monitoring results.
  • Write: Users in this group can see the object, review its monitoring results, and edit its settings. They cannot edit access rights settings.
  • Full: Users in this group can see the object, review its monitoring results, edit its settings, and edit access rights settings.

You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.

icon-book-arrowsFor more details on access rights, see section User Access Rights.

Smart URL Replacement

Instead of entering a complete address in the URL field of an HTTP sensor, you can just enter the protocol followed by a colon and three forward slashes (this means that you can enter either http:/// or https:///, or even a simple forward slash / as the equivalent for http:///). PRTG automatically fills in the parent device's IP address or DNS name in front of the third forward slash.

Whether this results in a valid URL or not depends on the IP address or Domain Name System (DNS) name of the parent device. In combination with cloning devices, smart URL replacement makes it easy to create many similar devices.

For example, if you create a device with the DNS name www.example.com and you add an HTTP sensor to it, you can provide values in the following ways:

  • If you enter https:/// in the URL field, PRTG automatically creates the URL https://www.example.com/
  • If you enter /help in the URL field, PRTG automatically creates and monitor the URL http://www.example.com/help
  • It is also possible to provide a port number in the URL field. It is taken over by the device's DNS name and is internally added, for example, http://:8080/

icon-i-round-redSmart URL replacement does not work for sensors that run on the probe device.

More

Knowledge Base: Are there any limits for using Cloud Ping and Cloud HTTP sensors?

Knowledge Base: What is the PRTG Cloud Bot?

Edit Sensor Channels

To change display settings, spike filtering, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, see section Sensor Channel Settings.

Notification Triggers

Click the Notification Triggers tab to change notification triggers. For detailed information, see section Sensor Notification Triggers Settings.

Others

For more general information about settings, see section Object Settings.

Sensor Settings Overview

For information about sensor settings, see the following sections:

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