<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: SSL Certificate Sensor
The SSL Certificate sensor monitors the certificate of a Secure Sockets Layer (SSL)/Transport Layer Security (TLS) secured connection.
The sensor also shows the certificate common name and the certificate thumbprint in the sensor message.
SSL Certificate Sensor
For a detailed list and descriptions of the channels that this sensor can show, see section Channel List.
Sensor in Other Languages
- Dutch: SSL Certificaat
- French: SSL certificat
- German: SSL-Zertifikat
- Japanese: SSL 証明書
- Portuguese: Certificado SSL
- Russian: Сертификат SSL
- Simplified Chinese: SSL 证书
- Spanish: Certificado SSL
Remarks
This sensor supersedes the deprecated HTTP Certificate Expiry sensor.
Add Sensor
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.
Basic Sensor Settings
Click the Settings tab of a sensor to change its settings.
Basic Sensor Settings
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Sensor Name
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Enter a name to identify the sensor.
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Parent Tags
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Shows tags that the sensor inherits from its parent device, parent group, and parent probe.
This setting is for your information only. You cannot change it.
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Tags
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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.
It is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with parentheses (()) or angle brackets (<>).
For performance reasons, it can take some minutes until you can filter for new tags that you added.
The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor:
- sslcertificate
- ssl
- certificate
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Priority
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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 () to the highest priority ().
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Timeout (Sec.)
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Enter a timeout in seconds for the TCP read request. Enter an integer value. The maximum timeout value is 300 seconds (5 minutes).
If the reply takes longer than this value, the sensor cancels the request and shows a corresponding error message.
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Usually, a sensor connects to the IP Address/DNS Name of the parent device. See the device settings for details. For some sensors, you can explicitly define the monitoring target in the sensor settings.
SSL Certificate Specific
SSL Certificate Specific
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Port
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Enter the number of the port to which this sensor connects. Enter an integer value. The default port is 443.
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Virtual Host (SNI Domain)
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Define the host name that the sensor tries to query if your server has multiple certificates on the same IP address and port combination. Enter a string.
In the case of virtual hosting, you must identify the specific certificate for a specific domain while all domains use the same IP address, you can use SNI, which is an extension of TLS.
If you select a Certificate Name Validation option below, the sensor compares the common name and optionally alternative names with the SNI. Leave this field empty to validate the common name with the host address of the parent device.
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Certificate Name Validation
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Define if you want the sensor to validate the certificate name:
- Do not compare common name (CN) with device address or SNI (default): Do not check if the certificate name is valid by comparing it with the address of the parent device or the defined SNI.
- Compare and show down status if common name (CN) and address/SNI do not match: Check the common name to validate the certificate name. If you define an SNI above, the sensor compares the common name with the SNI. If you do not define an SNI, the sensor uses the host address of the parent device. If the common name and the checked address/SNI do not match, the sensor shows the Down status.
- Compare and show down status if common name (CN)/alternative names (SAN) and address/SNI do not match: Check the common name and the Subject Alternative Names (SAN) to validate the certificate. If you define an SNI domain above, the sensor compares the common name and alternative names with the SNI. If you do not define an SNI, the sensor uses the host address of the parent device. If the common name or alternative names and the checked address/SNI do not match, the sensor shows the Down status.
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Connection Specific
Connection Specific
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SOCKS Proxy (v5 only)
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Define if the sensor uses a SOCKS proxy server for the sensor connection:
- Do not use SOCKS proxy (default): Directly connect to the target host without using a SOCKS proxy.
- Use SOCKS proxy: Connect using SOCKS5. Provide data for the SOCKS connection below.
Other SOCKS versions are not supported.
This sensor only supports SOCKS5 proxies. It does not support HTTP proxies.
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Server
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This setting is only visible if you select Use SOCKS proxy above. Enter the IP address or host name of the proxy server that the sensor uses for connection.
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Port
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This setting is only visible if you select Use SOCKS proxy above. Enter the port number of the proxy server that the sensor uses for connection.
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User Name
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This setting is only visible if you select Use SOCKS proxy above. If the proxy server requires authentication, enter a username.
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Password
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This setting is only visible if you select Use SOCKS proxy above. If the proxy server requires authentication, enter the password for the user you specified above.
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Debug Options
Debug Options
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Result Handling
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Define what PRTG does with the sensor result:
- Discard result: Do not store the sensor result.
- Store result: Store the last sensor result to the \Logs\sensors subfolder of the PRTG data directory on the probe system. The file names are Result of Sensor [ID].Data.txt, Result of Sensor [ID] (Certificate 0 in Certificate Chain).cer, Result of Sensor [ID] (Certificate 1 in Certificate Chain).cer, Result of Sensor [ID] (Certificate 2 in Certificate Chain).cer, Result of Sensor [ID] (Certificate Chain).txt, and Result of Sensor [ID] (Certificate).cer. This setting is for debugging purposes. PRTG overwrites these files with each scanning interval.
This option is not available when the sensor runs on the hosted probe of a PRTG Hosted Monitor instance.
In a cluster, PRTG stores the result in the PRTG data directory of the master node.
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You can use the debug option to get a logfile with information about the certificate chain. Additionally, certificates in the certificate chain are stored in the log folder (.cer files). This can help you, for example, if you have issues with the Root Authority Trusted channel of this sensor.
Sensor Display
Sensor Display
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Primary Channel
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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.
You can set a different primary channel later by clicking below a channel gauge on the sensor's Overview tab.
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Graph Type
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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.
You cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).
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Stack Unit
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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.
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Inherited Settings
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.
Scanning Interval
Click to interrupt the inheritance.
Scanning Interval
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Scanning Interval
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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:
- 30 seconds
- 60 seconds
- 5 minutes
- 10 minutes
- 15 minutes
- 30 minutes
- 1 hour
- 4 hours
- 6 hours
- 12 hours
- 24 hours
You can change the available intervals in the system administration of PRTG Network Monitor.
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If a Sensor Query Fails
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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:
- Set sensor to down immediately: Set the sensor to the Down status immediately after the first request fails.
- Set sensor to warning for 1 interval, then set to down (recommended): Set the sensor to the Warning status after the first request fails. If the second request also fails, the sensor shows the Down status.
- Set sensor to warning for 2 intervals, then set to down: Set the sensor to the Down status only after the third request fails.
- Set sensor to warning for 3 intervals, then set to down: Set the sensor to the Down status only after the fourth request fails.
- Set sensor to warning for 4 intervals, then set to down: Set the sensor to the Down status only after the fifth request fails.
- Set sensor to warning for 5 intervals, then set to down: Set the sensor to the Down status only after the sixth request fails.
Sensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval before they show the Down status. It is not possible to immediately set a WMI sensor to the Down status, so the first option does not apply to these sensors. All other options can apply.
If you define error limits for a sensor's channels, the sensor immediately shows the Down status. None of the interval options apply.
If a channel uses lookup values, the sensor immediately shows the Down status. None of the interval options apply.
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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.
Schedules, Dependencies, and Maintenance Window
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Schedule
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Select a schedule from the list. You can use schedules to monitor during a certain time span (days or hours) every week. Choose from:
- None
- Saturdays
- Sundays
- Weekdays
- Weekdays Eight-To-Eight (08:00 - 20:00)
- Weekdays Nights (17:00 - 09:00)
- Weekdays Nights (20:00 - 08:00)
- Weekdays Nine-To-Five (09:00 - 17:00)
- Weekends
You can create schedules, edit schedules, or pause monitoring for a specific time span. For more information, see section Schedules.
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Maintenance Window
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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:
- Do not set up a one-time maintenance window: Do not set up a one-time maintenance window. Monitoring is always active.
- Set up a one-time maintenance window: Set up a one-time maintenance window and pause monitoring. You can define a time span for the pause below.
To terminate an active maintenance window before the defined end date, change the time entry in Maintenance Ends to a date in the past.
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Maintenance Begins
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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.
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Maintenance Ends
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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.
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Dependency Type
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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:
- 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 a specific sensor is in the Down status or in the Paused status because of 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 the 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.
To 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.
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Dependency
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This setting is only visible if you enable Select a sensor above. Click and use the object selector to select a sensor on which the current object will depend.
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Dependency Delay (Sec.)
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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.
This 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.
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Access Rights
Click to interrupt the inheritance.
Access Rights
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User Group Access
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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:
- Inherited: Inherit the access rights settings of the parent object.
- No access: Users in this user group cannot see or edit the sensor. The sensor neither shows up in lists nor in the device tree.
- Read access: Users in this group can see the sensor and view its monitoring results. They cannot edit any settings.
- Write access: Users in this group can see the sensor, view its monitoring results, and edit its settings. They cannot edit its access rights settings.
- Full access: Users in this group can see the sensor, view its monitoring results, edit its settings, and edit its access rights settings.
For more details on access rights, see section Access Rights Management.
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Using Wildcards
You can use wildcards in the IP Address/DNS Name in the device settings. Wildcards that apply to only one level of the domain name are supported.
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*.wildcard.com for www.wildcard.com
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Works
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api.wildcard.com for api.wildcard.com
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Works
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contoso.com for contoso.com
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Works
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*.subapi.subapi2.wildcard.com for de.subapi.subapi2.wildcard.com
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Works
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*. *.wildcard.com for www.de.wildcard.com
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Not supported
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*.wildcard.com for de.subapi.wildcard.com
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Doesn't work
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www.contoso.com for contoso.com
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Doesn't work
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subapi.*.wildcard.com for subapi.dns.wildcard.com
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Doesn't work
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Channel List
Which channels the sensor actually shows might depend on the monitored device, the available components, and the sensor setup.
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Common Name Check
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If the common name or subject-alternative names match the host address or Server Name Identification (SNI) (if certificate name validation is enabled)
- Up status: CN/SAN Match, Disabled, Matches Device Address, Matches SNI
- Down status: CN/SAN Do Not Match SNI, Does Not Match Device Address, Does Not Match SNI
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Days to Expiration
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The days to expiration with a predefined lower warning limit (28 days) and lower error limit (7 days)
This channel is the primary channel by default.
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Downtime
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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.
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Public Key Length
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The public key length
- Up status:
- RSA keys: For 2048-bit keys (good security) and longer (perfect security)
- Elliptic Curve Cryptography (ECC) keys: For 128-bit and 192-bit keys (good security) and longer (perfect security)
- Warning status: For weak security
- Down status: For shorter keys (unsecure)
- Unknown status: Unknown
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Revoked
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If the certificate has been revoked
- Up status: No
- Warning status: Unable To Check Revocation Status
- Down status: Yes
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Root Authority Trusted
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If the certificate is trusted as root authority
- Up status: Yes
- Warning status: No
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Self-Signed
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If a self-signed certificate is used
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More
Knowledge Base
How can I configure the WinHTTP proxy settings for the SSL Certificate sensor?
What security features does PRTG include?
Sensor Settings Overview
For more information about sensor settings, see the following sections: