About SMTP Inbound and Outbound

SMTP listeners are responsible for receiving SMTP messages from other systems, establishing a connection, and initiating the email transfer process. The SMTP listener service has been developed to receive email messages sent using the Simple Mail Transfer Protocol (SMTP) as a result of the Microsoft IIS SMTP Service deprecation.

What you need to know

There is no authentication to log into the SMTP server.
The server accepts emails destined to any domain. It does not reject emails that are not addressed to its own domain by default as the IIS SMTP service did.
Administrators must ensure that other services are not trying to access the same port as the listener service. This may cause a conflict, for example, a SMTP listener and IIS SMTP running on the server at the same time.
The SMTP listener can manage attachments no greater than 20 MB. Emails with attachments greater than 20 MB will be rejected by the server.
The STARTTLS mode for receiving inbound connections is not supported. This method starts the connection in an unencrypted mode then changes to encrypted. Starting inbound connections either in unencrypted or SSL/TLS encrypted from the beginning of the connection is the only supported method.

Note: The SMTP listener service is only used for routing of inbound emails. The SMTP Relay Server is used to send outbound emails. Both services provide Administrators with a simple alternative IIS SMTP solution. Or you can install IIS SMTP on an operating system (Windows Server 2022 or lower) that supports both receiving inbound and sending outbound email messages if necessary.

Accessing the SMTP connector

You can access the SMTP connector by using the Server Administrator > Connectors node.

To access the SMTP connector

Start the Server Administrator.
Expand the Server Administrator tree.
Select Connectors. The Connectors details pane lists the connectors that are licensed with your server.
Double click the SMTP connector to view and edit its properties, if necessary.

Setting up SMTP Inbound and Outbound

Configuration of both the SMTP Listener Service inbound and SMTP Relay Server outbound can be accessed by using Message Server SMTP Services.

Administrators can use IIS SMTP on operating systems that support it. Or they can use Message Server SMTP Services which is the AccuRoute IIS SMTP alternative solution for inbound and outbound messages.

Note: You cannot have both solutions as part of the same configuration. For example, you cannot use IIS SMTP for inbound and use Message Server SMTP Services for outbound. Only one SMTP solution can be used for both inbound and outbound.

The Message Server SMTP Services solution is a simple alternative to IIS SMTP for operating systems that no longer support it.

In the Server Administrator, use Connectors to access Message Server SMTP Services.

To set up SMTP Inbound

In the Server Administrator, go to Connectors.
Select SMTP on the Server. The SMTP on the Server Properties dialog box appears.

See the SMTP Inbound Properties > General dialog box example below.

smtp on the server properties general dialog box

On the General tab, select Manager Connector Profile > Advanced. The Advanced SMTP Configuration dialog box appears.

See the Advanced SMTP Configuration dialog box example below.

advanced smtp configuration dialog box

Review the following option details and choose the option that works best for you and your organization.

SMTP Services

IIS SMTP Local

The IIS SMTP Local option is a default setting. IIS SMTP Local if supported by the operating system manages inbound and outbound emails using the normal folder structure IIS SMTP provides below the InetPub folder.

IIS SMTP with Custom Folders

The IIS SMTP With Custom folders option also allows IIS SMTP if supported by the operating system to manage inbound and outbound emails. You can configure custom folders in addition to the standard folders IIS SMTP uses for picking up and dropping emails.

Note: Contact Technical Support for assistance on this option and other Mail Root Folder properties.

Message Server SMTP Services

The Message Server SMTP Services option allows the AccuRoute implementation to handle both inbound and outbound emails

Inbound Port is the assigned port used for listening to incoming emails.
- The Use SSL for Inbound option is used to specify encryption for the inbound port.

Note: Administrators must obtain a SSL certificate from a trusted certificate authority for the SMTP server.

PFX files are typically encrypted and password-protected to safeguard the private key for security purposes.

The PFX file received from a trusted certificate authority must be copied to a folder local to the AccuRouteserver. The PFX file path is specified in the Path to PFX box, for example, c:\foldername\smtpcert.pfx.

The PFX file is created with a password and the Administrator must know and specify the password in the PFX Password box.

Outbound Server is used to specify the server address of a valid SMTP Outbound Relay in the network. It is the server used to send outbound emails to.

Note: Administrators are responsible for setting up their Outbound Server. The SMTP server address is used by the AccuRoute server for messages going outbound via SMTP.

Ensure that IIS SMTP is not active and listening on the same port when the Message Server SMTP Services options are selected.

Outbound Port 25 is the default port setting for the Inbound and Outbound ports. The port can be set to any port if necessary. Ports 25 and 587 are common ports associated with SMTP and can be changed to different port if necessary.
- The Use SSL for Outbound option is used to specify encryption for the outbound port.

What you need to know about Email Interceptor

For use with IIS SMTP or IIS SMTP Custom folders only

The email interceptor is an add-on that operates in IIS SMTP. When IIS SMTP gets an email for an external address, it sends it to that specific address. When Email Interceptor is enabled, it intercepts the email and sends it to the server's email processing folders so that it gets processed based on any rules configured before it is sent out to the external email address.

Note: This option is only used if scanners are part of an organization's workflow and there is a requirement to send a scanned document to an external email address where the server needs to perform some type of processing task, for example, OCR (Optical Character Recognition).