PRTG Manual: SMTP Sensor
The SMTP sensor monitors a mail server using the Simple Mail Transfer Protocol (SMTP).
The sensor can optionally send a test email with every check.
For a detailed list and descriptions of the channels that this sensor can show, see section Channel List.
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- This sensor does not support Secure Remote Password (SRP) ciphers.
- This sensor only supports IPv4.
- This sensor has a low performance impact.
You cannot add this sensor to the hosted probe of a PRTG Hosted Monitor instance. If you want to use this sensor, add it to a remote probe device.
Setting |
Description |
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Sensor Name |
Enter a 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. If the name contains angle brackets (<>), PRTG replaces them with braces ({}) for security reasons. For more information, see the Knowledge Base: What security features does PRTG include? |
Parent Tags |
The 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. |
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. 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:
|
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 () to the highest priority (). |
Setting |
Description |
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Timeout (Sec.) |
Enter a timeout in seconds for the request. Enter an integer. The maximum timeout value is 900 seconds (15 minutes). If the reply takes longer than this value, the sensor cancels the request and shows a corresponding error message. |
Port |
Enter the number of the port that the sensor uses to send an email via SMTP. The default port for unsecure connections is 25 and the default ports for secure connections are 465 or 587. The actual setting depends on the server that you connect to. Enter an integer. We recommend that you use the default value. If the connection is unsuccessful, try a different port number. |
Setting |
Description |
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SMTP Authentication Method |
Define if you want to use authentication for the SMTP connection:
|
User Name |
This setting is only visible if you select User name and password above. Enter a user name for SMTP authentication. Enter a string. |
Password |
This setting is only visible if you select User name and password above. Enter a password for SMTP authentication. Enter a string. |
HELO Ident |
Enter a server name for the HELO part of the mail protocol. For some mail servers, the HELO identifier must be the valid principal host domain name for the client host. For more information, see SMTP RFC 2821. If you leave this field empty, the value defaults to the computer name. Only ASCII characters are allowed. |
Setting |
Description |
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Transport-Level Security |
Define how the sensor handles the security of the connection:
If the sensor connects to a server via StartTLS, the connection is first established without connection security. After the connection has been established, the sensor sends a certain command (StartTLS) over the unsecured connection to negotiate a secure connection via SSL/TLS. If the sensor does not use StartTLS, the negotiation of a secure connection happens immediately (implicitly) so that no commands are sent in unencrypted plain text. If no secure connection is possible, no communication takes place. |
Setting |
Description |
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Email Handling |
Define the monitoring approach when connecting to the SMTP server:
|
From |
This setting is only visible if you select Send an email above. Specify the address of the sender of the email. Enter a valid email address. |
To |
This setting is only visible if you select Send an email above. Specify the address that PRTG sends the email to. Enter a valid email address. If you define more than one recipient, separate the individual email addresses with commas. |
Subject |
This setting is only visible if you select Send an email above. Specify the subject that the email contains. Enter a string or leave the field empty. |
Content |
This setting is only visible if you select Send an email above. Specify the body that the email contains. Enter a string or leave the field empty. |
Result Handling |
Define what PRTG does with the sensor result:
In a cluster, PRTG stores the result in the PRTG data directory of the master node. |
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. You can set a different primary channel later by clicking below a channel gauge on the sensor's Overview tab. |
Graph Type |
Define how different channels are shown for this sensor:
|
Stack Unit |
This setting is only visible if you select Stack channels on top of each other above. 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 these 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.
For more information, see section Root Group Settings, section Scanning Interval.
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.
For more information, see section Root Group Settings, section Schedules, Dependencies, and Maintenance Window (default).
For more information, see section Root Group Settings, section Access Rights.
Which channels the sensor actually shows might depend on the target 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 |
Response Time |
The response time This channel is the primary channel by default. |
KNOWLEDGE BASE
What security features does PRTG include?