Community Knowledge Base

Gateway Setup in SmarterMail

Gateways perform a crucial function when running mail servers, especially in very busy environments. Their primary mission is to handle the flow of inbound or outbound traffic, ensuring timely and proper delivery of messages. As such, they handle the majority of the traffic, easing the sending and delivery of email to its intended recipient.

SmarterMail simplifies the ability to set up and configure gateways. Here, you select the Gateway mode, which dictates the type of gateway being set up.

If any gateways have already been created, they will be displayed here. Otherwise, this page will be blank.

Types of Gateway

Outbound gateways allow you to reduce the load on your primary server by using a secondary server to process outbound mail. Gateway servers can also be used to combat blacklisting. If the gateway server gets blacklisted, simply rotate the primary IP on the network card to a different one to send out on the new IP.

There are two types of Outbound Gateway: Round Robin or Specific Domains.

"Round Robin", means that when multiple gateways are configured, domains will use one then use the next to send mail, cycling through each gateway.

"Specific Domains" allows administrators to select a specific gateway for specific domains when those domains are being set up. (Or, it's possible to set the gateway for a domain after it's been set up.)

To add a new outbound gateway, click the New button. When adding or editing an entry, the following settings will be available:

  • Gateway Mode - The type of gateway to add. For an outbound gateway, select either Round Robin or Specific Domains, depending on the type of outbound gateway you want to add.
  • Server Address - The IP address or hostname of the gateway server.
  • Port - The port used to connect to the gateway server.
  • Encryption - Select the type of encryption from the list.
  • Status - The status of the outbound gateway. To temporarily turn off the outbound gateway, select Disable from the list.
  • Enable Authentication - Enable this setting if your outbound gateway server requires authentication. Then enter the Auth Username and Password below.
  • Auth Username - The authorized username of the gateway server.
  • Auth Password - The corresponding password for the authorized username.
  • Verify Connection before Save - Enabling this means SmarterMail will test the connection to the Server Address and Port prior to actually connecting to the gateway.

The purpose of gateways labeled "Backup MX" or "Domain Forward" are to reduce server load by pre-processing incoming messages prior to the messages being handed off for delivery to the primary SmarterMail server. For example, spam checks and antivirus scans should be performed by these types of gateway, especially in larger environments, as they are standalone servers that simply process incoming messages, so they don't act as primary mail servers. This frees up the primary server so all it has to do is deliver messages to individual users.

A "Backup MX" will only receive messages when your primary server is down.

A "Domain Forward" allows you to easily send mail through one server to another and permit you to have a single point of entry for inbound SMTP traffic. When messages come in for a forwarded domain, they are handled just like any other incoming message, which includes being handled based on the Spool settings for the server. (I.e., Settings > General > Spool.) For example, if a delivery delay has been established for the server, messages are also delayed accordingly. In addition, an inbound server can run external virus or spam scanners, which can reduce the load on your existing network servers.

To set the server as either a Backup MX or Domain Forward, click the New button and select your option. When adding or editing an entry, the following settings will be available:

  • Gateway Mode - The function that the inbound gateway will perform: Backup MX or Domain Forward.
  • IP Addresses (single, range or CIDR block) - The IP address, or range of IP addresses, of the primary mail server.
  • Status - New gateways default to a status of Enabled. To temporarily stop an inbound gateway, you can change the status to Disabled.
  • Description - A friendly name for the inbound gateway.
  • SMTP User Verification - Available when setting up a Domain Forward, this setting makes SmarterMail verify that a recipient exists when accepting mail from the gateway.


NOTE: This card is only available if the gateway mode is set to Domain Forward, so it's used to specify which domains the gateway will accept mail for:

  • Domain Verification - The method used by the inbound gateway to determine if a domain is valid or not: Specified Domains or All But Specified Domains. List the domain(s) below (one entry per field).

SmarterMail Gateway

This allows you to specify whether the gateway being set up will be used for another SmarterMail server. If you're seeing slowness in mail deliveries, and the gateway is set up as a Backup MX or Domain Forward AND SmarterMail Gateway, and the spool count is high, it's possible something is tying up the transfer of mail from the gateway to the SmarterMail server.

  • Enable SmarterMail Gateway Mode - Select this option to indicate that the gateway is being created for a separate SmarterMail server that is actually hosting the email.
  • SmarterMail URL - The webmail URL for the SmarterMail server the gateway is being set up for. For example, you have one SmarterMail server being set up as a Domain Forward "inbound" gateway (e.g.,, and it's forwarding mail to a domain (or to domains) on a separate SmarterMail server (e.g., The information input as the "SmarterMail URL" will be the primary URL for the SmarterMail server the gateway will forward email to, or Use of a SmarterMail gateway allows administrators the abiltiy to use web services to verify the users and domains, if needed. NOTE: SmarterMail uses a cache of the domains and users on a server, so if there are any changes (e.g., additions, modifications like enabling/disabling users or domains, or deletions) these changes may not be reflected for up to 10 minutes until the cache is refreshed.
  • SmarterMail Username - The identifier used to log in to the SmarterMail server.
  • SmarterMail Password - The corresponding password used to log in to the SmarterMail server.
  • User Verification - The method used by the inbound gateway to determine if a user is valid or not. Note: If none is selected, the inbound gateway server will accept all email addresses for the domain. If Web service is selected, the inbound gateway will check with the primary mail server for a list of valid email addresses.


NOTE: This card is only available if the gateway mode is set to Domain Forward or Backup MX.

As Backup MX or Domain Forward gateways act on mail coming into the server, it's possible to specify the actions taken for the messages that are classified as spam Low, Medium, or High. If a message is processed that is NOT marked with a spam level, actions can still be taken as well.