PRTG Manual: HTTP Transaction Sensor
The HTTP Transaction sensor monitors an interactive website, such as a web shop, by performing a transaction using a set of HTTP URLs. The sensor monitors whether logins or shopping carts work properly.
For a detailed list and descriptions of the channels that this sensor can show, see section Channel List.
- Dutch: HTTP (Transactie)
- French: Transaction (HTTP)
- German: HTTP (Transaktion)
- Japanese: HTTP トランザクション
- Portuguese: Transação HTTP
- Russian: Транзакция HTTP
- Simplified Chinese: HTTP 处理
- Spanish: Transacción HTTP
- This sensor has a high performance impact. Use it with care. We recommend that you use no more than 200 sensors of this sensor type on each probe.
- This sensor does not support Secure Remote Password (SRP) ciphers. If you need to use SRP ciphers, use the Alternate/Compatibility Mode in the sensor settings.
- This sensor supports smart URL replacement.
- This sensor supports the IPv6 protocol.
- See the Knowledge Base: Configuration tips for HTTP Transaction sensors needed
- See the Knowledge Base: Which user agent should I use in the HTTP Advanced sensor's settings?
The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the settings that are required to create the sensor. You can change nearly all settings on the sensor's Settings tab after creation.
Click the Settings tab of a sensor to change its settings.
Setting |
Description |
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Sensor Name |
Enter a name to identify the sensor. |
Parent Tags |
Shows tags that the sensor inherits from its parent device, parent group, and parent probe.
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Tags |
Enter one or more tags. Confirm each tag with the Spacebar key, a comma, or the Enter key. You can use tags to group objects and use tag-filtered views later on. Tags are not case-sensitive. Tags are automatically inherited.
The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor:
|
Priority |
Select a priority for the sensor. This setting determines the position of the sensor in lists. The highest priority is at the top of a list. Choose from the lowest priority ( |
Setting |
Description |
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Timeout (Sec.) |
Enter a timeout in seconds for all HTTP requests. Enter an integer value. The maximum value is 900 seconds (15 minutes).
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Single URL Timeout (Sec.) |
Enter a timeout in seconds for one single HTTP request. Enter an integer value. The maximum value is 900 seconds (15 minutes).
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Setting |
Description |
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Monitoring Engine |
Choose the monitoring engine that the sensor uses:
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SSL/TLS Method |
This option is only visible if you select Alternate/Compatibility Mode above. Choose from:
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Check SSL Certificates |
This option is only visible if you select Alternate/Compatibility Mode above. Specify if the sensor checks the certificate of the URL:
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This sensor implicitly supports SNI, an extension to the Transport Layer Security (TLS) protocol.
Setting |
Description |
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Download Limit (KB) |
Enter a number that defines the maximum amount of data (in kilobytes) that the sensor transfers per request.
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Cookie Management |
Select if you want to allow cookies for the transaction:
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User Agent |
Choose which user agent string the sensor sends when it connects to the target URL:
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Custom User Agent |
This setting is only visible if you enable Use a custom string above. Enter the string that the sensor uses as the user agent when it connects to the target URL. |
Result Handling |
Define what PRTG does with the web page that is loaded at the URL:
|
Setting |
Description |
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Authentication |
Define if authentication is necessary on the web page:
|
User Name |
If the proxy requires authentication, enter the user name for the proxy login.
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Password |
This setting is only visible if you select Web page needs authentication above. Enter a password. |
Authentication Method |
This setting is only visible if you select Web page needs authentication above. Select the authentication method that the URL uses:
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You can define up to 10 different transaction URLs, which are all called in a row. If the transaction can be completed, the sensor shows the Up status. Using this mechanism, you can set up extended monitoring with multiple URLs.
Enter settings for at least one transaction URL. You can use as many steps as necessary and disable the other steps.
Setting |
Description |
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Transaction Step #x |
This setting is available for URL #2 through #10. Define if you want to use this step for the transaction check:
|
URL |
Enter the URL that the sensor connects to. If you enter an absolute URL, the sensor uses this address independently of the IP Address/DNS Name setting of the parent device.
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Request Method |
Select an HTTP request method to determine how the sensor requests the URL:
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Postdata |
This setting is only visible if you select POST above. Enter the data part for the POST request.
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Require Keyword |
Define if the sensor checks the result at the URL for keywords:
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Response Must Include |
This setting is only visible if you select Set sensor to warning if keyword is missing or Set sensor to error if keyword is missing above. Define the search string that must be part of the result at the URL.
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Exclude Keyword |
Define if the sensor checks the result at the URL for keywords:
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Response Must Not Include |
Define a string that must not be part of the result at the URL. If the data includes this string, the sensor shows the Down status and displays this string along with the affected URL in the sensor message. Enter a string.
|
Setting |
Description |
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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.
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Graph Type |
Define how different channels are shown for this sensor:
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Stack Unit |
This setting 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. |
By default, all of the following settings are inherited from objects that are higher in the hierarchy. We recommend that you change them centrally in the root group settings if necessary. To change a setting for this object only, click under the corresponding setting name to disable the inheritance and to display its options.
For more information, see section Inheritance of Settings.
Proxy Settings for HTTP Sensors
Click to interrupt the inheritance.
The proxy settings determine how a sensor connects to a URL. You can enter data for an HTTP proxy server that sensors use when they connect via HTTP or HTTPS.
This setting only applies to HTTP sensors and how they monitor. To change the proxy settings for the PRTG core server, see section Core & Probes.
Setting |
Description |
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IP Address/DNS Name |
Enter the IP address or Domain Name System (DNS) name of the proxy server. If you leave this field empty, HTTP sensors do not use a proxy. |
Port |
Enter the port number of the proxy. The default is 8080. Enter an integer value. |
User Name |
If the proxy requires authentication, enter the user name for the proxy login.
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Password |
If the proxy requires authentication, enter the password for the proxy login.
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Click to interrupt the inheritance.
Setting |
Description |
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Scanning Interval |
Select a scanning interval from the dropdown list. The scanning interval determines the amount of time that the sensor waits between two scans. Choose from:
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If a Sensor Query Fails |
Select the number of scanning intervals that the sensor has time to reach and to check a device again if a sensor query fails. Depending on the option that you select, the sensor can try to reach and to check a device again several times before the sensor shows the 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 the Warning status. Choose from:
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Schedules, Dependencies, and Maintenance Window
You 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 schedules, dependencies, and maintenance windows. They are active at the same time as the parent objects' settings.
Setting |
Description |
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Schedule |
Select a schedule from the list. You can use schedules to monitor during a certain time span (days or hours) every week. Choose from:
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Maintenance Window |
Select if you want to set up a one-time maintenance window. During a maintenance window, monitoring stops for the selected object and all child objects. They show the Paused status instead. Choose between:
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Maintenance Begins |
This setting 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 one-time maintenance window. |
Maintenance Ends |
This setting 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 one-time maintenance window. |
Dependency Type |
Select a dependency type. You can use dependencies to pause monitoring for an object depending on the status of a different object. You can choose from:
|
Dependency |
This setting is only visible if you enable Select a sensor above. Click |
Dependency Delay (Sec.) |
This setting is only visible if you select Select a sensor above. Define a time span in seconds for the dependency delay. After the master sensor for this dependency returns to the Up status, PRTG additionally delays the monitoring of the dependent objects by the time span you define. This can prevent false alarms, for example, after a server restart or to give systems more time for all services to start. Enter an integer value.
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Click to interrupt the inheritance.
Setting |
Description |
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User Group Access |
Define the user groups that have access to the sensor. You see a table with user groups and group access rights. The table contains all user groups in your setup. For each user group, you can choose from the following group access rights:
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Instead of entering a complete address in the URL field of an HTTP sensor, you can only 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/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, you can use smart URL replacement to create many similar devices.
For example, if you create a device with the DNS name www.mycompany.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.mycompany.com/
- If you enter /help in the URL field, PRTG automatically creates and monitor the URL http://www.mycompany.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/
Smart URL replacement does not work for sensors that run on the probe device.
Which channels the sensor actually shows might depend on the monitored device, the available components, and the sensor setup.
Channel |
Description |
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Downtime |
In the channel table on the Overview tab, this channel never shows any values. PRTG uses this channel in graphs and reports to show the amount of time in which the sensor was in the Down status in percent. |
Sum |
The loading time of the complete transaction in milliseconds (msec)
|
Time of URL [#] |
The loading time of single URLs in msec |
Knowledge Base
Configuration tips for HTTP Transaction sensors needed
Which user agent should I use in the HTTP Advanced sensor's settings?
What security features does PRTG include?
My HTTP sensors don't work. What can I do?
For more information about sensor settings, see the following sections: