Having port 25 open is a good start, but it doesn’t automatically mean your server is ready to send emails reliably. You need to decide whether you’re building your own mail server or using an email delivery service such as Amazon SES, SendGrid, or Resend.
1. What should you do next?
If you want to send legitimate emails from your own domain, follow this order:
- Check your server’s IP reputation. A new IP may have no sending history, and an IP with a poor reputation may have delivery problems.
- Configure your domain’s DNS. Set up SPF, DKIM, and DMARC to authenticate your outgoing emails.
- Configure reverse DNS (PTR). Your server’s IP should resolve to a hostname that resolves back to the same IP.
- Choose your sending method. You can run your own mail transfer agent (MTA) or use a third-party SMTP relay.
- Test delivery. Send a few messages to inboxes you control and check authentication results, spam placement, and bounce handling.
Should you warm up the server?
Yes, if you’re going to send email from a new IP. However, warming up isn’t simply sending increasing numbers of messages.
Build a reputation gradually by sending expected, wanted emails to recipients who have opted in. Monitor bounces, spam complaints, and delivery failures. Don’t start with a large mailing list.
Important: Port 25 being open only means SMTP traffic may be possible. It doesn’t guarantee that your hosting provider permits outbound email or that receiving mail servers will accept your messages.
2. Which email service should you use?
Here are three options worth considering.
Amazon Web Services
— Amazon SES
Official documentation:
Amazon SES
SES is worth considering if your main priority is cost-effective email delivery.
- Supports SMTP and API-based sending.
- Requires you to verify your sending domain or email address.
- New accounts start in a sandbox with restrictions.
- You must request production access to send to unverified recipients.
