---
title: "Why Outbound SMTP Relay Services Are Essential For Robust Email Deliverability Of Marketing Emails | DuoCircle"
description: "Email marketing has gained much significance over the past few years."
image: "https://www.duocircle.com/images/og-default.png"
canonical: "https://www.duocircle.com/blog/outbound-smtp/why-outbound-smtp-relay-services-are-essential-for-robust-email-deliverability-of-marketing-emails/"
---

Quick Answer

Outbound SMTP relay services exist because peer-to-peer mail and stock business email accounts cap how many messages you can send and how cleanly they reach the inbox. A relay is a third-party SMTP service that takes outbound mail from your application or marketing tool and delivers it on infrastructure tuned for volume, reputation, and compliance. The benefits are concrete: bypass per-account send limits, keep marketing email out of spam folders, isolate bulk traffic from regular business mail, and add malware checks on the way out. Common patterns include open relays (insecure, avoid), closed or private relays (more secure), Gmail SMTP relay (about 100 free messages a day, fine for low volume), and Office 365 SMTP relay for line-of-business apps. Use a dedicated relay provider for any campaign that runs at real volume.

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![Why Outbound SMTP Relay Services Are Essential For Robust Email Deliverability Of Marketing Emails](https://media.mailhop.org/duocircle/images/stock/cloud-email.jpg) 

Email marketing has gained much significance over the past few years. _Every organization worth its salt uses email marketing as one of its primary promotional strategies_. Sending bulk emails using the standard email servers has its limitations. The ideal solution is to use an **SMTP relay service** to ensure guaranteed delivery of marketing and other emails to the prospective customer’s inbox. Let us discuss the concept of [SMTP services](/email/outbound-smtp) and understand its significance.

_SMTP or Simple Mail Transfer Protocol is used to deliver outbound emails to the respective recipients_, and also to accept inbound emails if required. **SMTP email services** become significant because the peer-to-peer email services hosted through the cloud or accessed on a web browser cannot suffice for mass email campaigns. Most email providers have specific limits as to the number of emails one can send on such peer-to-peer networks.

## The Concept Of The SMTP Relay Service

Now let’s see what an SMTP relay service is. The [outbound email service](/email/outbound-smtp) is similar to the functioning of a post office. The difference is that the email service provider (ESP) connects to the configured SMTP server for delivering the email message. If the recipient address belongs to the same domain, it is a simple email transfer. If the recipient belongs to a different domain, the system must relay the email to the client-server. _A software or third-party service that helps achieve this relaying of emails is known as SMTP relay service_.

Thus, _Mail relay **SMTP services** are those that use trusted third-parties for delivering bulk emails_. Generally, business entities specializing in sending large volumes of emails, such as newsletters, delivery confirmations, and password resets, use these SMTP relay software.

[![](https://media.mailhop.org/duocircle/images/2024/03/SMTP-Email-Marketing-Statistics.jpg)](https://media.mailhop.org/duocircle/images/2024/03/SMTP-Email-Marketing-Statistics.jpg)

## The Importance Of SMTP Relay Services In Today’s Changing Business World

SMTP relay service has gained in significance because of the increasing volume of outbound emails\*\*.\*\*

- _The peer-to-peer email service provider cannot cater to bulk emailing jobs_. Hence, it can affect the [email delivery rate](https://sendpulse.com/support/glossary/delivery-rate#:~:text=Email%20delivery%20rates%20are%20calculated,some%20emails%20may%20have%20bounced.), thereby clogging the bandwidth and cause unnecessary delays. An SMTP relay service provider can do a better job of handling the deliverability of emails.
- Generally, standard email service providers restrict the number of email recipients. It can be a challenge to send thousands of marketing emails to subscribers. _Subscribing to SMTP mail relay services like SMTP relay O365 or SMTP relay Gmail can efficiently resolve such issues_.
- Using an SMTP relay service is beneficial as _it prevents the email from reaching the recipients’ spam or junk folders_.
- Business entities can outsource **outbound email services** for managing large email jobs without affecting regular business email communications.

## Know The Different Types Of SMTP Relay Services Available

The most common and popular SMTP service providers for outbound email services are the following\*\*.\*\*

- **_Open Mail Relay_**, Open Mail Relay is an **insecure third-party relay service** that sends outbound emails from your internal and external networks. The SMTP relay service that caters only to internal messages is known as a closed mail relay. _A closed or private mail relay is **more secure** compared to an open mail relay._
- **_SMTP Relay Gmail_**, One of the best SMTP relay free service providers is Gmail. This service allows the business entity to send up to 100 free daily emails. It is ideal for businesses that have a low volume of outbound emails.
- **_SMTP Relay O365_**, Office 365 offers the facility to use LOB (line-of-business) apps to [streamline the process](https://blog.mastykarz.nl/integrating-office-365-web-applications-addins-lob-azure-api-apps/) of using the client database. This facility lets you access data and send reminders to the customers when they have business appointments. It offers you a bunch of other features as well.

## Setting Up One of The Most Common SMTP Relay Service: Gmail

_SMTP Relay Gmail allows customers to send business emails such as newsletters, notifications, and contact forms_. Setting up your Gmail SMTP server is easy. The following are the essential settings.

- The outgoing email server is smtp.gmail.com.
- Click on the ‘Yes’ option for user authentication and providing secure connections (TLS or SSL, depending on the mail client plugin)
- Use your Gmail account user id and password.
- Use Port 465 if you need SSL settings and Port 584 if you require TLS.

## The Final Question: Why Do You Need An SMTP Relay Software?

_Though setting up an SMTP relay service is easy, it is better to use SMTP relay software_. Generally, the email marketing process uses specific outbound email templates or outbound email examples that can get **marked as spam** emails. As a _reputed SMTP relay software prevents labelling messages as spam_, businesses can end up protecting their reputation when sending bulk outbound emails. Secondly, a reputed SMTP relay service also offers **protection against malware**. Therefore, it only makes sense for businesses to subscribe to SMTP relay services so that they have one less thing to worry about, i.e., Email Marketing.

The use of email marketing campaigns is a necessity for all business enterprises in these competitive times. _A peer-to-peer email service provider has its limitations_. Using the services of a quality SMTP relay service can prove highly helpful in ensuring that the emails do reach the recipients’ inbox without getting labeled as spam. It ends up protecting the businesses’ reputation and ensures a successful email marketing strategy in place.

![Brad Slavin](https://media.mailhop.org/dmarcreport/images/team/brad-slavin.jpg) 

Brad Slavin 

General Manager

General Manager at DuoCircle. Product strategy and commercial lead across the email security portfolio.

## Secure your email infrastructure

Protect, authenticate, and deliver. Contact our team to find the right solution.

[Contact Sales](/contact/) [Explore Products](/products/) 

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