> ## Documentation Index
> Fetch the complete documentation index at: https://docs.edbb.com/llms.txt
> Use this file to discover all available pages before exploring further.

# SMTP Port 25 Rate Limit

> Learn how EDBB handles outbound SMTP traffic on port 25 and what limits apply to protect IP reputation.

export const CtaButton = ({label, link, openInNewTab}) => <a className="custom-cta-button" href={link} target={openInNewTab ? "_blank" : "_self"} rel={openInNewTab ? "noreferrer" : undefined}>
    {label}
  </a>;

# Outbound SMTP Policy

<Info>
  EDBB keeps TCP port 25 open so you can run your own mail services. To protect shared IP reputation, outbound traffic is rate-limited to <strong>8 packets per second</strong> with an initial burst of 16 pps.
</Info>

***

## Why We Rate-Limit Port 25

<CardGroup cols={2}>
  <Card title="🛡️ IP Reputation">
    Throttling prevents sudden spam bursts that could land shared IP ranges on blocklists.
  </Card>

  <Card title="⚖️ Fair Usage">
    Keeps one VPS from monopolizing outbound SMTP bandwidth.
  </Card>

  <Card title="🚫 Abuse Deterrence">
    Makes the platform less attractive for spammers while staying practical for legitimate email.
  </Card>

  <Card title="📅 Consistent Policy">
    Applies to every VPS created after 24 February 2025. The limit is not adjustable per account.
  </Card>
</CardGroup>

***

## What This Means for You

* Transactional email, server alerts, and admin notifications operate normally.
* Bulk campaigns or newsletters should use dedicated providers (SendGrid, Mailgun, Amazon SES, etc.).
* Exceeding the limit will slow delivery but won’t block single messages outright.
* EDBB enforces a strict no-spam policy—verified abuse leads to suspension without refund.

***

## Best Practices

1. Configure SPF, DKIM, and DMARC to improve deliverability.
2. Monitor mail queues and bounce reports; most issues stem from application misconfiguration rather than the rate limit.
3. Keep abuse contacts current in WHOIS/RDAP so you can respond quickly to complaints.
4. For high-volume sending, integrate with a reputable SMTP relay service.

Need clarifications for compliance requirements? Reach out to EDBB Support via the messenger or by email before launching your mail workload.

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