Are smarthost and SMTP relay the same thing?

Yes, smarthost and SMTP relay terms are generally used interchangeably. Both mean routing emails through an intermediate server. Technically, smarthost is the name of the server that provides SMTP relay service.

Is it safe to use a smarthost?

Using a trusted smarthost provider is safe. Professional providers like MXGate offer TLS/SSL encryption, DKIM signing, and SPF compliance. Your emails are transmitted encrypted and their contents are not read.

Some providers offer limited free plans, but paid plans are recommended for professional use. MXGate offers a 14-day free trial. Paid plans are typically priced based on the number of emails sent.

What is a Smarthost? SMTP Relay Guide (2026)

What is a Smarthost?

Smarthost (smart server) is an intermediate SMTP server where emails are routed before being sent to the recipient. It is also known as a "relay host" or "mail relay".

Simple Definition: Instead of sending emails from its own IP address, your mail server sends them through the smarthost. The smarthost forwards these emails from its own clean IP pool, increasing delivery success.

Today, smarthost usage has become a standard practice especially for hosting providers, ISPs, and organizations sending high-volume emails. According to Radicati Group research, 67% of enterprise companies use some form of relay service for email delivery.

How Does a Smarthost Work?

An email travels through the smarthost from your mail server until it reaches the recipient's inbox: Your Mail Server (Postfix, Exim, cPanel) → Smarthost (Clean IP Pool) → Recipient (Inbox).

Step by Step Process

Email Creation: A user or application sends an email.
Routing to Smarthost: The mail server forwards the email to the smarthost instead of sending it directly (with SMTP auth).
Processing and Filtering: The smarthost applies spam checking, virus scanning, and content filtering.
Delivery: The email is delivered to the recipient from a clean IP address, achieving a high delivery rate.

Why Use a Smarthost?

IP Reputation Protection

Your server's IP address does not get blacklisted. Even if a customer sends spam, your IP is not affected.

99%+ Delivery Rate

Thanks to sending from a clean IP pool, emails reach the inbox instead of the spam folder.

Bypassing ISP Restrictions

Works seamlessly even on networks with port 25 blocking. The relay service is provided over port 587 (TLS).

Centralized Monitoring

Monitor all outgoing emails from a single panel — statistics, logs, and reports.

%67 — Enterprise relay usage rate
%99.9 — Delivery success rate
%85 — Spam reduction rate

Setup Guide

MXGate Smarthost setup takes only 3 minutes. Here are quick start guides for popular systems:

cPanel/WHM Setup

WHM > Exim Configuration Manager > Advanced Editor
Find the "Smart Host (SMTP Route)" section
Enter smtp.mxgate.com.tr:587
Enter your SMTP Authentication credentials

Plesk Setup

Plesk > Tools & Settings > Mail Server Settings
Enable the "External SMTP Server" option
Enter Relay host: smtp.mxgate.com.tr
Save your SMTP auth credentials

Postfix Setup

Add the following settings to your /etc/postfix/main.cf file:

relayhost = [smtp.mxgate.com.tr]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_security_level = encrypt

Smarthost vs SMTP Relay vs Mail Gateway

These terms are often confused. Here are the differences:

Smarthost — An intermediate server that forwards emails. Used for outgoing email routing.
SMTP Relay — Same meaning as smarthost. Usually used for SaaS services.
Mail Gateway — Inbound + outbound email security. Used for comprehensive email protection.
MTA (Mail Transfer Agent) — Email server software: Postfix, Exim, Sendmail.

Conclusion

Using a smarthost is critical, especially for hosting providers and organizations sending high-volume emails. It protects your IP reputation, increases your delivery rate, and centralizes your email management.

What is a Smarthost? Comprehensive SMTP Relay Guide