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. They also offload the processing of messages, easing the work done by the actual SmarterMail server. As such, they handle the majority of the traffic sending and/or delivering email to its intended recipients.

SmarterMail simplifies the ability to set up and configure gateways, allowing administrators to quickly and easily set up both inbound and outbound gateways. If any gateways have already been created, they will be displayed on the Gateways tab. If no gateways exist, this tab will be blank.

Types of Gateway

There are essentially two types of gateway: Inbound and Outbound.

Outbound Gateways

There are two types of Outbound Gateway: "Round Robin" or "Specific Domains". Outbound gateways are similar to inbound as they handle the pre-processing of messages prior to them being sent off to recipient email servers. Again, this pre-processing can include antispam and anti-malware checks. Outbound gateways can also be used for more granular email processing like the configuration of throttling limits. For example, if a hosting provider has a particular email plan targeted towards email marketers, these domains can be funneled through a particular outgoing gateway that throttles the ability to send emails from these domains to a set number to mitigate the potential for the domains to become blacklisted.

"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.)

Inbound Gateways

There are two types of inbound gateway: "Backup MX" and "Domain Forward". In both cases, the purposes of an inbound gateway is 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 can be performed by these types of gateways, 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.

Note: When setting up a Backup MX, it's important to ensure that the Maximum Message Size configured on the Backup MX server matches the value set for your primary server. In addition, any gateway setup as a Backup MX cannot also act as an outbound gateway.

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.

Adding Gateways

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

Options

Server Address - The IP address or hostname of the gateway server.
Port - The port used to connect to the gateway server.
Description - A detailed, yet friendly description for the type of gateway set up, it's purpose, etc.
Enable SMTPUTF8 - Toggle this to enable the use of UTF-8 encoding (i.e., non-ASCII) for email addresses, message headers, subject lines, etc. for SMTP traffic.
Enable SmarterMail Gateway Mode - Select this option to indicate that the gateway being set up is another SmarterMail server. This allows communication via API and also things like spool count when setting an outbound gateway.
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., gateway1.example.com), and it's forwarding mail to a domain (or to domains) on a separate SmarterMail server (e.g., mail1.example.com). The information input as the "SmarterMail URL" will be the primary URL for the SmarterMail server the gateway will forward email to, or https://mail1.example.com. 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.
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.

Outbound Gateway

Enable Outbound - Toggle this to set up an outbound gateway.
Outbound Mode - Select the type of outbound gateway to set up: Round Robin or Specific Domains.
Encryption - Select the type of encryption 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.

Inbound Gateway

Enable Inbound - Toggle this to set up an inbound gateway.
Inbound Mode - Select the type of inbound gateway to set up: Domain Forward or Backup MX.
User Verification Mode - The method used by the inbound gateway to determine if a user is valid or not: None, SMTP, or Web Service. .

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. If SMTP is selected, when setting up a Domain Forward, this setting makes SmarterMail verify that a recipient exists when accepting mail from the gateway.

Domain Verification - Used for Domain Forward only, this allows an administrator to select whether specific domains will be handled by the forward, all BUT specific domains will be handled by the forward, or whether a web service will be used for the verification.
Domains - Used for Domain Forward only, this is the list of specific domains handled by the gateway or, conversely, the list of domains NOT handled by the gateway, depending on the Domain Verification that's set. This list goes away when the Domain Verification is set to Web Service.
Enable Spam Checks - 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. When toggled on, a new Inbound Spam Checks card will display.