How to Send Emails via ZateHost SMTP Relay (Port 25 Block Bypass)

Send your emails securely and reliably — no port 25 unblock needed.

Introduction

To maintain a secure and spam-free network, ZateHost blocks outgoing port 25 by default on all VPS servers. This policy helps prevent abuse, spam, and IP blacklisting, ensuring a safer and more reliable mail environment for all customers.

However, you can still send emails smoothly and securely using our SMTP Relay Service. This relay allows your outgoing emails to pass through trusted mail servers, providing better deliverability, encryption, and compliance with all major email providers.

SMTP Relay Details

Our relay service is powered by a high-reputation mail delivery network, ensuring that your emails reach inboxes consistently and securely.

Configuring Postfix (Linux VPS)

If your VPS uses Postfix as its mail transfer agent, follow these steps:

1. Edit the Postfix main configuration file:

   sudo nano /etc/postfix/main.cf

2. Add or update the following lines:

   relayhost = [relay.zatehost.com]:587
   smtp_use_tls = yes
   smtp_tls_security_level = encrypt
   smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt

3. Save the file and restart Postfix:

   sudo systemctl restart postfix

Once restarted, your VPS will automatically relay all outgoing emails through ZateHost’s SMTP service.

Configuring Exim (cPanel / WHM)

For servers running cPanel/WHM, follow these steps:

1. Log in to WHM → Exim Configuration Manager
2. Locate the Smarthost Support option
3. Enter the relay host:

   relay.zatehost.com:587

4. Save the configuration and restart Exim.

Your cPanel mail server will now use ZateHost’s relay for outbound email delivery.

SPF Record Setup (Required for Deliverability)

To authorize ZateHost’s relay servers to send email on behalf of your domain, you must add an SPF record in your domain’s DNS settings. This ensures your emails pass SPF validation and are not marked as spam.

If your domain already has an SPF record, merge our include directive with your existing one:

v=spf1 a mx include:spf.zatehost.com include:_your_existing_spf_source ~all

This combined record ensures that ZateHost’s relay is authorized while preserving any existing SPF permissions.

Verifying Your Setup

After updating DNS, you should verify that your SPF record is valid using one of the following tools:

• MXToolbox SPF Checker
• Kitterman SPF Validator
• Command line:

  dig txt yourdomain.com +short

A correct response should include:

"v=spf1 a mx include:spf.zatehost.com ~all"

Summary

With this setup, your server can send outgoing emails reliably without requiring a port 25 unblock, while maintaining high deliverability and security standards.

Why Use the ZateHost SMTP Relay

• Prevents IP blacklisting and spam issues
• Improves delivery rates to Gmail, Outlook, Yahoo, and other providers
• No authentication required when using ZateHost IPs
• Fully encrypted communication via TLS
• Simple configuration for both Postfix and Exim

Conclusion

ZateHost’s SMTP Relay provides a secure and reliable solution for sending outgoing mail from your VPS. By using our relay and configuring the correct SPF record, you can ensure your emails are delivered safely to recipients’ inboxes without delays or spam filtering issues.

ZateHost SMTP Relay — Secure, Reliable, and Fully Optimized for Deliverability.