--- title: "What Is SMTP Relay – How You Can Leverage SMTP Relay Services | DuoCircle" description: "Join the thousands of organizations that use DuoCircle Find out how affordable it is for your organization today and be pleasantly surprised.Interested in" image: "https://www.duocircle.com/images/og-default.png" canonical: "https://www.duocircle.com/content/mail-relay-smtp/what-is-smtp-relay/" --- Content # What Is SMTP Relay – How You Can Leverage SMTP Relay Services Join the thousands of organizations that use DuoCircle Find out how affordable it is for your organization today and be pleasantly surprised.Interested in [ Talk to an Expert → ](/contact/) [ See what we make ](/products/) ## What Is SMTP Relay – How You Can Leverage SMTP Relay Services [Fix Your SPF Errors Now](/content/spf-permerror) Email marketing is vital for all organizations. Businesses also need to send transactional emails such as those confirming orders and shipping to win their client’s trust. A lot of the time, however, such emails will end up in the spam folder of recipients. _An SMTP relay service prevents this and guarantees that an organization’s emails reach intended recipients_. Before we can understand what **SMTP relays** are, let us first take a look at the [SMTP protocol](https://www.geeksforgeeks.org/simple-mail-transfer-protocol-smtp/) itself. ![mail relay smtp](https://media.mailhop.org/duocircle/images/2020/05/spam-filter-gateway.png) ### SMTP Explained The Simple Mail Transfer Protocol, otherwise called _SMTP, is employed by mail servers to deliver outgoing emails_. By contrast, the [POP and IMAP protocols](https://www.siteground.com/tutorials/email/protocols-pop3-smtp-imap/) are used to receive emails from a mail server. ### What Is SMTP Relay? An SMTP relay or [Message Transfer Agent](https://en.wikipedia.org/wiki/Message%5Ftransfer%5Fagent) (MTA) transfers emails from one mail server to another. Here’s how it works – - When an email is sent, the initial message sends the details of the route with a destination address to the SMTP relay. - The relay uses the Domain Name Service (DNS) and domain address from the email to determine the destination ID. - The relay then transmits the mail to a message transfer agent. - The email data traverses through multiple **message transfer agents** before arriving in the receiver’s mailbox. ![smtp relay gmail](https://media.mailhop.org/duocircle/images/2020/05/spam-filter-service.png)![outbound smtp](https://media.mailhop.org/duocircle/images/2020/05/spam-gateway-1.png) ### What Is an SMTP Relay Service? As explained earlier, _SMTP relays transfer emails from one mail server to another_, but this is a technically complicated process. An [SMTP relay service](/content/mail-relay-smtp/smtp-relay-service) is a managed service that helps organizations send their outgoing bulk and transactional emails by routing emails through a **trusted third party**. Almost all email services make use of such services for sending their emails. Some things SMTP relay service providers do are – - **Scan For Malware** – Emails are scanned for spam commercials and phishing content. - **Reputation Verification** – The DNS and internal reputation systems verify domain reputation. - **Spam Trap Checks** – Spam trap emails should not be on a sending list to avoid problems. - **Ensures Proper Configuration** – Improper configuration of an SMTP relay can lead to it becoming an [open mail relay](/content/mail-relay-smtp/open-mail-relay). _Such relays are abused by spammers to send emails._ ### Why Should Organizations Use Mail Relay SMTP Services? There are several reasons organizations should use [mail relay SMTP](/content/mail-relay-smtp) services. - **Simpler** – Managing email is complicated for time-sensitive transactional emails or mass marketing. - **Deliverability Issues** – ISPs set maximum limits on the number of emails that can be sent. - **Avoid Blacklists** – Regulator blacklists can become a problem if sending messages in bulk without using SMTP services. - **Easily Manage Batch and Automated Emails** – Using SMTP via a third party removes all deliverability issues associated with such emails. ![smtp relay free](https://media.mailhop.org/duocircle/images/2020/05/cloud-based-email-spam-filter.png)![smtp relay gmail](https://media.mailhop.org/duocircle/images/2020/05/email-spam-filter-service.png) ### Integration Of SMTP Relay Software With Hardware _SMTP servers require SMTP relay software to be installed and configured for the proper delivery of emails_. Such software helps _improve efficiency_ and lets email travel in an optimal, well-defined route interconnected by a network of servers. ### Free SMTP Relays vs. Paid Ones Smaller businesses can leverage free SMTP relays like the [SMTP relay Gmail](/content/mail-relay-smtp/smtp-relay-gmail) or SMTP relay O365 provides. The [SMTP relay free](/content/mail-relay-smtp/smtp-relay-free) services, however, come at a trade-off to scalability. Google, for example, lets you send only 3000 emails a month. _Scammers might also be sharing such servers and thus harm deliverability_. Therefore, for growing businesses, getting a premium SMTP service would be the ideal choice, where they can choose and set up features and customizations per their business needs. _SMTP can guarantee the delivery of bulk and transactional emails._ Moreover, SMTP technologies are easier to implement, and enterprises can save a lot of capital due to the low-cost hardware and software solutions provided by **SMTP relay services**.![smtp relay o365](https://media.mailhop.org/duocircle/images/2020/05/email-spam-filtering-services.png) ##### Join the thousands of organizations that use DuoCircle --- Find out how affordable it is for your organization today and be pleasantly surprised. [Outbound SMTP - Sign Up FREE](/email/outbound-smtp)Interested in our Partner Program for MSPs and VARs? Visit Our [MSP Partner Program](/msp-partner-program). ## Ready to talk? Same-day response from someone technical. We tell you yes or no quickly. If yes, we get to work. 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