PRTG Manual: IMAP Sensor

The IMAP sensor monitors an email server using the Internet Message Access Protocol (IMAP).

The sensor can show the following:

IMAP Sensor

IMAP Sensor

Sensor in Other Languages

  • Dutch: IMAP
  • French: IMAP
  • German: IMAP
  • Japanese: IMAP
  • Portuguese: IMAP
  • Russian: IMAP
  • Simplified Chinese: IMAP
  • Spanish: IMAP

Remarks

  • This sensor does not support Secure Remote Password (SRP) ciphers.
  • If you use content checks, we recommend that you use a dedicated IMAP account that is only checked by PRTG. Editing mails in the mailbox of the monitored IMAP account can lead to false alarms or malfunctions of this sensor.
  • This sensor might not work properly when monitoring subfolders of mailboxes. If it has to check subsequent emails with identical subjects, emails coming in later might not be recognized.
  • Emails that arrive during the Daylight Saving Time (winter time to summer time) change might not be processed properly. If you experience this issue, delete the respective emails.
  • This sensor has a medium performance impact.

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.

Basic Sensor Settings

Click the Settings tab of a sensor to change its settings.

i_round_blueUsually, 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.

Setting

Description

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.

i_round_blueIf 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

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

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.

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

The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor:

  • imapsensor
  • mailsensor

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 (i_priority_1) to the highest priority (i_priority_5).

Connectivity

Setting

Description

Timeout (Sec.)

Enter a timeout in seconds for the request. If the reply takes longer than this value, the sensor cancels the request and shows a corresponding error message. Enter an integer value. The maximum value is 900 seconds (15 minutes).

Port

Enter the number of the port that the sensor uses to connect via IMAP. The default port for unsecure connections is 143 and the default port for secure connections is 993. The actual setting depends on the server you are connecting to. Enter an integer value. We recommend that you use the default value.

i_round_blueIf you do not get a connection, try a different port number.

Connection Security

Define the security of the connection:

  • Use transport-level security if available using StartTLS (default): The sensor tries to connect to the server via a Secure Sockets Layer (SSL)/Transport Layer Security (TLS) secured connection and StartTLS. If the server does not support this, the sensor tries to connect without connection security.
  • Use transport-level security if available: The sensor tries to connect to the server via an SSL/TLS-secured connection. If the server does not support this, the sensor tries to connect without connection security.
  • Enforce transport-level security using StartTLS: The sensor tries to connect to the server via an SSL/TLS-secured connection and StartTLS. If the server does not support this, the sensor shows a Down status.
  • Enforce transport-level security: The sensor tries to connect to the server via an SSL/TLS-secured connection. If the server does not support this, the sensor shows a Down status.

i_round_blueIf 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.

i_round_blueIf 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.

Sensor Behavior

Setting

Description

General Behavior

This sensor can additionally check the content of all incoming emails:

  • Check connectivity only, do not process emails (default): Only check the availability of the IMAP server and check if a login is successful. Do not process any emails in the IMAP email account.
  • Count emails in this mailbox: Count the emails in the defined mailbox.
  • Process emails in this mailbox: Log in to the IMAP email account and check the emails that it contains. Define further options below.

Result Handling

Define what PRTG does with the sensor result:

  • Discard result: Do not store the sensor result.
  • Store result: Store the last sensor result in the \Logs\sensors subfolder of the PRTG data directory on the probe system. The file names are Result of Sensor [ID].txt and Result of Sensor [ID].Data.txt. This setting is for debugging purposes. PRTG overwrites these files with each scanning interval.

i_podThis option is not available when the sensor runs on the hosted probe of a PRTG hosted by Paessler instance.

i_round_blueIn a cluster, PRTG stores the result in the PRTG data directory of the master node.

Authentication

Setting

Description

Username

Enter a username for IMAP authentication. Enter a string.

Password

Enter a password for IMAP authentication. Enter a string.

i_round_redThe password must not contain spaces or percent signs (%).

Folder Name

Enter the name of a folder in the mailbox (for example, the IMAP folder) that the sensor checks. The default value is Inbox. Unless you set a last message date check below, the sensor always looks at all emails contained in the mailbox.

i_round_redEnsure that you do not manually edit emails in this mailbox with a different email client because this can result in malfunctions of this sensor's email identification.

Filter Emails in Inbox

i_round_blueThis settings section is only visible if you choose to process the emails in the mailbox.

Setting

Description

Only Include Emails with Matching "From"

Define if you want to check the "From" field of the emails:

  • Do not check (default): Do not process this field in emails.
  • Check using simple string search: Process this field in emails using a simple string in plain text.
  • Check using regular expression: Process this field in emails using a regular expression (regex).

When using a search, the sensor scans all emails from the newest to the oldest.

i_round_bluePRTG supports Perl Compatible Regular Expression (PCRE) regex. For more details, see section Regular Expressions.

i_round_redThe sensor finishes the scan with the first match. This means that after it has found a match in one email, the sensor does not perform any further checks in older emails.

Search for

This setting is only visible if you enable a "from" check above. Enter an email address or a regular expression that the "From" field of the email must contain or match.

Only Include Emails with Matching "Subject"

Define if you want to check the "Subject" field of the emails:

  • Do not check (default): Do not process the subject of emails.
  • Check using simple string search: Process the subject of emails using a simple string in plain text.
  • Check using regular expression: Process the subject of emails using a regex.

When using a search, the sensor scans all emails from the newest to the oldest.

i_round_bluePRTG supports Perl Compatible Regular Expression (PCRE) regex. For more details, see section Regular Expressions.

i_round_redThe sensor finishes the scan with the first match. This means that after it has found a match in one email, the sensor does not perform any further checks in older emails.

Search for

This setting is only visible if you enable a "subject" check above. Enter a simple string in plain text or a regular expression that the "Subject" field of the email must contain or match.

Only Include Emails with Matching Email Body

Define if you want to check the email body of the emails:

  • Do not check (default): Do not process the email body.
  • Check using simple string search: Process the email body using a simple string in plain text.
  • Check using regular expression: Process the email body using a regex.

When using a search, the sensor scans all emails from the newest to the oldest.

i_round_bluePRTG supports Perl Compatible Regular Expression (PCRE) regex. For more details, see section Regular Expressions.

i_round_redThe sensor finishes the scan with the first match. This means that after it has found a match in one email, the sensor does not perform any further checks in older emails.

Search for

This setting is only visible if you enable checking the email body above. Enter a simple string in plain text or a regular expression that the body of the email must contain or match.

Only Include Recent Emails

Define if you want to check all emails in the mailbox or only mails that were received during the last few hours:

  • Do not check message age (default): Always check all emails that the mailbox contains.
  • Emails must be younger than: Only check emails that were received during the last few hours. Define below.

Maximum Age in Hours

This setting is only visible if you enable the message age check above. Enter the maximum age in hours. The sensor only processes emails that are younger. Enter an integer value.

If No Email Matches the Above Filters

Define which status the sensor shows if it does not find any email in the mailbox that matches the defined filters:

  • Set sensor to up status (default): Set the sensor to the Up status if it does not find any email in the mailbox that matches the defined filters.
  • Set sensor to warning status: Set the sensor to the Warning status if it does not find any email in the mailbox that matches the defined filters.
  • Set sensor to down status: Set the sensor to the Down status if it does not find any email in the mailbox that matches the defined filters.

Message

This setting is only visible if you define the Warning or Down status as no matching behavior above. Define the message that the sensor shows if it did not find any matching emails.

Validate Latest Email

i_round_blueThis settings section is only visible if you choose to process the emails in the mailbox.

i_round_redThe sensor only validates the latest email that matches the filters above. If the sensor does not find a matching email, it does not perform any email validation.

Setting

Description

For the Latest Email that Matches, Set Sensor to "Warning" Status

Define in which cases the sensor shows the Warning status.

  • Never (default): Never set this sensor to the Warning status based on email content.
  • Always: Always set this sensor to the Warning status if any emails could be identified.
  • If subject contains: Set the sensor to the Warning status if the subject of the found email contains the search text you define below.
  • If subject does not contain: Set the sensor to the Warning status if the subject of the found email does not contain the search text you define below.
  • If email body contains: Set the sensor to the Warning status if the body of the found email contains the search text you define below.
  • If email body does not contain: Set the sensor to the Warning status if the body of the found email does not contain the search text you define below.

Search Method

This setting is only visible if you select an "if" condition above. Define the method with which you want to search for the respective condition:

  • Simple string search: Search the email subject or body with a simple string in plain text.

i_round_blueThe characters * and ? work as placeholders. * stands for no number or any number of characters and ? stands for exactly one character (as known from the Windows search). You cannot change this behavior. The literal search for these characters is only possible with a regular expression.

  • Regular expression: Search the email subject or body with a regex.

i_round_bluePRTG supports Perl Compatible Regular Expression (PCRE) regex. For more details, see section Regular Expressions.

Search String

This setting is only visible if you select an "if" condition above. Define the string that you want to search the email subject or body for. You can enter a simple string in plain text or a regular expression.

i_round_redThe search string must be case sensitive.

Warning Message

This setting is only visible if you select a "warning" condition above. Define the message that the sensor shows for the Warning status.

Based on Message Age, Set Sensor to "Warning" Status

Define if you want to check the age of the latest matching email in the mailbox:

  • Never (default): Do not check the age of the email.
  • If email is older than: Set the sensor to the Warning status if the found email is older than you define below.

Message Age in Hours

This setting is only visible if you enable the message age check above. Enter the maximum age in hours. If the processed email is older, the sensor shows the Warning status. Enter an integer value.

i_round_redEnsure you do not manually edit emails in this mailbox with a different email client because this can result in malfunctions of the message age check.

For the Latest Email that Matches, Set Sensor to "Down" Status

Define in which cases the sensor shows the Down status.

  • Never (default): Never set this sensor to the Down status based on email content.
  • Always: Always set this sensor to the Down status if any emails could be identified.
  • If subject contains: Set the sensor to the Down status if the subject of the found email contains the search text you define below.
  • If subject does not contain: Set the sensor to the Down status if the subject of the found email does not contain the search text you define below.
  • If email body contains: Set the sensor to the Down status if the body of the found email contains the search text you define below.
  • If email body does not contain: Set the sensor to the Down status if the body of the found email does not contain the search text you define below.

Search Method

This setting is only visible if you select an "if" condition above. Define the method with which you want to search for the respective condition:

  • Simple string search: Search the email subject or body using a simple string in plain text.

i_round_blueThe characters * and ? work as placeholders. * stands for no number or any number of characters and ? stands for exactly one character (as known from the Windows search). You cannot change this behavior. The literal search for these characters is only possible with a regular expression.

  • Regular expression: Search the email subject or body with a regex.

i_round_bluePRTG supports Perl Compatible Regular Expression (PCRE) regex. For more details, see section Regular Expressions.

Search String

This setting is only visible if you enable an "if" condition above. Define the string that you want to search the email subject or body for. You can enter a simple string in plain text or a regular expression.

i_round_redThe search string must be case sensitive.

Error Message

This setting is only visible if you select a "down" condition above. Define the message that the sensor shows for the Down status.

Sensor Display

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.

i_round_blueYou can set a different primary channel later by clicking b_channel_primary below a channel gauge 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.
    i_round_redYou cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).

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.

Inherited Settings

By default, all of the following settings are inherited from objects that are higher in the hierarchy. You should change them centrally in the root group settings if necessary. To change a setting for this object only, click b_inherited_enabled under the corresponding setting name to disable the inheritance. You then see the options described below.

i_square_cyanFor more information, see section Inheritance of Settings.

Scanning Interval

Click b_inherited_enabled 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:

  • 30 seconds
  • 60 seconds
  • 5 minutes
  • 10 minutes
  • 15 minutes
  • 30 minutes
  • 1 hour
  • 4 hours
  • 6 hours
  • 12 hours
  • 1 day

i_round_blueYou can change the available intervals in the system administration on PRTG on premises installations.

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:

  • 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.

i_round_blueSensors 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.

i_round_blueIf you define error limits for a sensor's channels, the sensor immediately shows the Down status. None of the interval options apply.

i_round_blueIf a channel uses lookup values, the sensor immediately shows the Down status. None of the interval options apply.

Schedules, Dependencies, and Maintenance Window

i_round_blueYou 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:

  • 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

i_square_cyanYou can create schedules, edit schedules, or pause monitoring for a specific time span. For more information, see section Schedules.

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:

  • Not set (monitor continuously): 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 a the pause below.

i_round_blueTo terminate an active maintenance window before the defined end date, change the time entry in Maintenance Ends to a date in the past.

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:

  • 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.

i_round_blueTo 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 setting is only visible if you enable Select a sensor above. Click b_search_light and use the object selector to select a sensor on which the current object will depend.

Dependency Delay (Sec.)

This setting is only visible if you enable 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.

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 b_inherited_enabled 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:

  • 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.

i_square_cyanFor more details on access rights, see section Access Rights Management.

More

i_square_blueKNOWLEDGE BASE

How can I monitor my backup software to be sure backup succeeded last night?

My IMAP sensor does not process HTML emails correctly using regex. What can I do?

Can I analyze multipart emails using the IMAP sensor?

My IMAP sensor does not find emails when I check for message date. What can I do?

Sensor Settings Overview

For more information about sensor settings, see the following sections: