Creating MX records for email server routing

Question

Pulumi · Accepted Answer

MX (Mail Exchange) records are DNS records that are necessary for delivering email to your domain. When you send an email to someone at `example.com`, the sending mail server looks up the MX record for `example.com` to determine where to deliver the email.

To create MX records, you use a DNS provider's resources in Pulumi. Below, I will show you how to create MX records using the AWS Route 53 service as it is a commonly used DNS service provider.

Here is an explanation of each step in the program:
1. Import the necessary AWS Pulumi package.
2. Initialize a new Pulumi stack that defines our resources.
3. Create a hosted zone for the domain if you don't already have one.
4. Add MX records to the hosted zone pointing to your email server with the necessary priority.

Priorities are used when you have multiple email servers; lower numbers have higher priority. You configure the "Value" with the priority and the mail server's domain name (for example, "10 mail.example.com").

Here's the Pulumi TypeScript program that accomplishes this:

```typescript
import * as aws from "@pulumi/aws";

// Replace the following with your domain and mail server details
const domainName = "example.com.";
const mailServer = "mail.example.com.";  // Your mail server's address
const mailServerPriority = 10;           // Lower number = higher priority

// Create a new AWS Route 53 hosted zone for your domain, if you don't have one
const zone = new aws.route53.Zone("myZone", {
    name: domainName,
});

// Create an MX record that points to your mail server
const mxRecord = new aws.route53.Record(`${domainName}-mx`, {
    zoneId: zone.zoneId,
    name: domainName,
    type: "MX",
    ttl: 300, // Time-to-live in seconds
    records: [`${mailServerPriority} ${mailServer}`], // Priority and server address
});

// Export the name servers of our domain
export const nameServers = zone.nameServers;
```

In this code:
- We import the AWS package which provides us with the ability to interact with AWS services.
- We define our domain and mail server information.
- We create a new hosted zone for our domain, which will allow us to define DNS records for that domain.
- We create a new MX record in our hosted zone that points to our specified mail server with the desired priority.
- We export the name servers of our domain so that we can configure our domain name registrar with these values for the domain to work properly.

After running this Pulumi program with `pulumi up`, Pulumi will provide you with the values of any exports; in this case, the name servers for your domain. You will need to set these name servers at your domain registrar for your domain to use these records.

Please replace `example.com` and `mail.example.com` with your actual domain and mail server details before deploying this code.