PRTG Manual: SMTP&POP3 Round Trip Sensor
The SMTP&POP3 Round Trip sensor monitors the time it takes for an email to reach a Post Office Protocol version 3 (POP3) mailbox using the Simple Mail Transfer Protocol (SMTP). It sends an email using the parent device (an SMTP server) and then scans a dedicated POP3 mailbox until the email comes in.
The SMTP&POP3 Round Trip sensor automatically deletes these emails from the mailbox as soon as PRTG has retrieves them. Emails only remain in the mailbox if a timeout or a restart of the PRTG core server occurs during sensor runtime.
For a detailed list and descriptions of the channels that this sensor can show, see section Channel List.
- Dutch: SMTP & POP3 Round Trip
- French: SMTP & POP3 aller-retour
- German: SMTP&POP3-Übermittlung
- Japanese: SMTP&POP3 ラウンドトリップ
- Portuguese: Ida e volta SMTP&POP3
- Russian: Цикл SMTP и POP3
- Simplified Chinese: SMTP 和 POP3 往返
- Spanish: Ida y vuelta SMTP&POP3
Consider the following remarks and requirements for this sensor:
Remark |
Description |
---|---|
Performance impact |
This sensor has a high performance impact. We recommend that you use no more than 200 of this sensor on each probe. |
Parent device |
This sensor requires that the parent device is an SMTP server. |
SRP ciphers |
This sensor does not support Secure Remote Password (SRP) ciphers. |
Microsoft 365 mailboxes |
This sensor does not support Microsoft 365 mailboxes. If you want to monitor a Microsoft 365 mailbox, use the Microsoft 365 Mailbox sensor. |
IPv4 |
This sensor only supports IPv4. |
Dedicated email accounts |
Use dedicated email accounts with this sensor. Make sure that each sensor uses its own email accounts. |
The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor:
- mailsensor
- pop3sensor
- roundtrip
For more information about basic sensor settings, see section Sensor Settings.
Setting |
Description |
---|---|
From |
Specify the email address of the email's sender. Enter a valid email address. |
To |
Specify the address that PRTG sends the emails to. Enter a valid email address. You can only enter one email address. |
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. Only ASCII characters are allowed. |
Step 1: Send Email Using Parent Device (SMTP Server)
In this step, you configure how the sensor sends the emails. The sensor uses the IP Address/DNS Name of the parent device (an SMTP server).
Setting |
Description |
---|---|
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. |
Timeout for SMTP Connection (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. |
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. |
Additional Text for Email Subject |
PRTG automatically creates the subject part of the round trip email. The subject consists of the string PRTG Roundtrip Mail:, followed by a unique globally unique identifier (GUID) to correctly identify the email in the IMAP mailbox, for example, PRTG Roundtrip Mail: {5E858D9C-AC70-466A-9B2A-55630165D276}. Use this field to place your custom text before the automatically created text. |
Setting |
Description |
---|---|
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. |
Step 2: Check a POP3 Mailbox until Email Arrives
In this step, you configure how to receive the sent emails.
Setting |
Description |
---|---|
IP Address/DNS Name |
Specify the POP3 server. Enter a valid IP address or Domain Name System (DNS) name. |
Port |
Specify the port that the sensor uses for the POP3 connection. The default port for unsecure connections is 110 and the default port for secure connections is 995. The actual setting depends on the server you connect to. Enter an integer. We recommend that you use the default value. If the connection is unsuccessful, try a different port number. |
Connection Interval (Sec.) |
Enter the number of seconds the sensor waits between two connections to the POP3 server. PRTG continuously checks the mailbox in this scanning interval until the email arrives. Enter an integer. |
Maximum Trip Time (Sec.) |
Enter the maximmum number of seconds an email can take to arrive in the POP3 mailbox. PRTG continuously checks the mailbox in the interval that you specify above until the email arrives. If it does not arrive within the maximum trip time, the sensor triggers an error message. Enter an integer. |
POP3 Authentication Method |
Select the authentication method for the POP3 connection:
|
User Name |
This setting is only visible if you select User name and password or 128-bit MD5 hash value (APOP) above. Enter a user name for POP3 authentication. Enter a string. |
Password |
This setting is only visible if you select User name and password or 128-bit MD5 hash value (APOP) above. Enter a user name for POP3 authentication. Enter a string. |
Setting |
Description |
---|---|
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 |
---|---|
Result Handling |
Define what PRTG does with the sensor result:
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. |
Setting |
Description |
---|---|
Primary Channel |
Select a channel from the list to define it as the primary channel. In the device tree, PRTG displays the last value of the primary channel 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 this sensor shows different channels:
|
Stack Unit |
This setting is only visible if you select Stack channels on top of each other above. Select a unit from the list. PRTG stacks all channels with this unit 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.
Which channels the sensor actually shows might depend on the target device, the available components, and the sensor setup.
Channel |
Description |
---|---|
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 (POP3) |
The response time of the POP3 server |
Response Time (SMTP) |
The response time of the SMTP server |
Total |
The sum of the response time of the SMTP server and the POP3 server This channel is the primary channel by default. |
KNOWLEDGE BASE
What security features does PRTG include?