How to Open Port 25 on AWS?

Port 25 is the standard SMTP port used for sending email between mail servers. Amazon Web Services blocks outbound connections on port 25 by default on all EC2 instances and Lambda functions as a measure to prevent spam and protect the reputation of their IP addresses. This affects anyone trying to run their own mail server, an email marketing platform, or any application that needs to send email via SMTP directly.

To officially request that AWS remove the port 25 restriction on your account, you need to submit a request through the AWS Support Center. The request form asks for information including your intended use case, the volume of email you expect to send, whether you have an unsubscribe mechanism, and how you plan to handle bounces and complaints. AWS reviews these requests manually, and the approval process typically takes anywhere from 1 to 7 business days. There is no guarantee of approval — AWS can decline the request if they have concerns about your use case.

If your request is approved, AWS removes the throttle on port 25 at the account level for the specific regions you requested. You still need to configure proper PTR (reverse DNS) records, SPF, DKIM, and DMARC for good email deliverability. AWS SES (Simple Email Service) is often recommended as an alternative to direct SMTP because it handles the sending infrastructure, but SES itself also has sending limits that require a similar approval process to increase.

For developers and businesses who cannot wait or who get denied, there is a much simpler path: purchasing a cloud account from a provider that does not block port 25 by default. BuyAWSAccount.com offers port 25 open accounts on DigitalOcean (starting at $99 for 3 open-port droplets), Linode ($130), IBM Cloud ($80), Kamatera ($45), and Atlantic.Net ($199). These accounts have port 25 already configured and operational, so you can deploy your mail server immediately without any approval process.

The most cost-effective port 25 open account for most use cases is the Kamatera port 25 open account at $45, which includes per-minute billing for maximum cost efficiency. For higher-volume email infrastructure, DigitalOcean's open port 25 accounts supporting up to 25 droplets ($299) provide the most scalable option.