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.
For a detailed list and descriptions of the channels that this sensor can show, see section Channel List.
- 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
- Enter the Domain Name System (DNS) name in the settings of the parent device exactly as it is written in your certificate. You can also use wildcards.
- To check the revocation status of a certificate, the sensor uses WinHTTP to auto-detect the proxy server to use. You can also manually define a server. If you do not define a proxy server, PRTG uses the default WinHTTP proxy settings. For more information, see the Knowledge Base: How can I configure the WinHTTP proxy settings for the SSL Certificate sensor?
- 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 Channel Settings.
- This sensor supports the IPv6 protocol.
- This sensor has a very low performance impact.
- This sensor uses lookups to determine the status values of one or more 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.
This sensor supersedes the deprecated HTTP Certificate Expiry 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.
Click the Settings tab of a sensor to change its settings.
Setting |
Description |
---|---|
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.
|
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 ( |
Timeout (Sec.) |
Enter a timeout in seconds for the TCP read request. Enter an integer value. The maximum timeout value is 300 seconds (5 minutes).
|
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.
Setting |
Description |
---|---|
Port |
Enter the number of the port to which this sensor connects. Enter an integer value. The default port is 443. |
Virtual Host (SNI Domain) |
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.
|
Certificate Name Validation |
Define if you want the sensor to validate the certificate name:
|
Setting |
Description |
---|---|
SOCKS Proxy (v5 only) |
Define if the sensor uses a SOCKS proxy server for the sensor connection:
|
Server |
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. |
Port |
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. |
User Name |
This setting is only visible if you select Use SOCKS proxy above. If the proxy server requires authentication, enter a username. |
Password |
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. |
Setting |
Description |
---|---|
Result Handling |
Define what PRTG does with the sensor result:
|
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.
Setting |
Description |
---|---|
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.
|
Graph Type |
Define how different channels are shown for this sensor:
|
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.
Click to interrupt the inheritance.
Setting |
Description |
---|---|
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:
|
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:
|
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 |
---|---|
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:
|
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:
|
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.
|
Click to interrupt the inheritance.
Setting |
Description |
---|---|
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:
|
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.
Example |
Result |
---|---|
*.wildcard.com for www.wildcard.com |
Works |
api.wildcard.com for api.wildcard.com |
Works |
contoso.com for contoso.com |
Works |
*.subapi.subapi2.wildcard.com for de.subapi.subapi2.wildcard.com |
Works |
*. *.wildcard.com for www.de.wildcard.com |
Not supported |
*.wildcard.com for de.subapi.wildcard.com |
Doesn't work |
www.contoso.com for contoso.com |
Doesn't work |
subapi.*.wildcard.com for subapi.dns.wildcard.com |
Doesn't work |
Which channels the sensor actually shows might depend on the monitored device, the available components, and the sensor setup.
Channel |
Description |
---|---|
Common Name Check |
If the common name or subject-alternative names match the host address or Server Name Identification (SNI) (if certificate name validation is enabled)
|
Days to Expiration |
The days to expiration with a predefined lower warning limit (28 days) and lower error limit (7 days)
|
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. |
Public Key Length |
The public key length
|
Revoked |
If the certificate has been revoked
|
Root Authority Trusted |
If the certificate is trusted as root authority
|
Self-Signed |
If a self-signed certificate is used
|
Knowledge Base
How can I configure the WinHTTP proxy settings for the SSL Certificate sensor?
What security features does PRTG include?
For more information about sensor settings, see the following sections: