--- title: "What Does an SMTP Server Do? | 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/smtp-as-a-service/smtp-server/" --- Content # What Does an SMTP Server Do? 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 Does an SMTP Server Do? [Fix Your SPF Errors Now](/content/spf-permerror) Practically everyone uses email; [281 billion](https://www.lifewire.com/how-many-emails-are-sent-every-day-1171210) are sent per day, after all. It’s a valuable communication tool, especially with prospects and clients. Surprisingly, for something so widely used, email is not very understood by most people. To help you grasp the inner workings of email, _we’ll explain what an SMTP server is and how it’s used for email._ ![](https://media.mailhop.org/duocircle/images/2019/02/email-phishing-protection.png) ### SMTP: explained SMTP stands for “[Simple Message Transfer Protocol](https://whatis.techtarget.com/definition/SMTP-Simple-Mail-Transfer-Protocol).” _This is the protocol your email client uses when you have outgoing messages._ In relation to a physical mail system, the [SMTP as a service](/content/smtp-as-a-service) would be the mail truck, since it’s what transports emails from your inbox to the recipient’s inbox. ### SMTP server: explained Now that you know what an [SMTP service](/content/smtp-as-a-service/smtp-service) is, we can explain what an **SMTP server** is. Like a regular server, it powers the protocol. It takes the information it has and gives it to other computers, which lets it find the correct inboxes for delivery. But _SMTP servers don’t work in both directions; they can only deliver outgoing mail, not receive incoming messages_. The counterpart for receiving emails would be [POP3](https://whatismyipaddress.com/pop3) or IMAP. MORE: Know [SMTP Pricing](/content/smtp-as-a-service/smtp-pricing) ![](https://media.mailhop.org/duocircle/images/2019/02/account-phishing-attack.png)![](https://media.mailhop.org/duocircle/images/2019/02/protect-from-phishing.png) ### How an SMTP server works Although the process of sending an email appears to be instant, _there are a few steps outgoing mail has to take before it reaches the recipients’ inboxes_. Here’s the entire process: 1. In your email client, you fill out the form (recipient’s name, address, and your message) 2. and press send. 3. Your email client connects to your domain’s SMTP server. Once it’s connected, it sends all the email information to the server. This includes the email addresses and content. 4. If both addresses are from the same domain name, then there’s no relay needed. Your message will be sent to the recipient’s POP3 or IMAP server. If the domain names are different, the [SMTP relay service](/content/smtp-as-a-service/smtp-relay-service) will have to relay your message. It’ll get the recipient’s IP address by accessing the DNS (Domain Name Server). 5. Now that your [SMTP relay](/content/smtp-as-a-service/smtp-relay) server has the recipient’s IP address, it can connect to their SMTP server. 6. The recipient’s SMTP server scans your email. If it’s from a non-blacklisted IP address or domain, then it’ll accept it into the POP3 or IMAP server. ### Use a third-party SMTP server provider _Using a third-party [free SMTP server](/content/smtp-as-a-service/free-smtp-server) provider is highly beneficial for your organization._ You’ll be able to send both bulk and transactional emails without fear of them ending up in spam folders. Not only that, but you can get **protection against malware** too. MORE: [Email pricing](/content/smtp-as-a-service/email-pricing) for providers ![](https://media.mailhop.org/duocircle/images/2019/02/advanced-phish-protection.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. [Talk to an Expert→](/contact/)[See what we make](/products/) ```json {"@context":"https://schema.org","@type":"Organization","name":"DuoCircle LLC","url":"https://www.duocircle.com","logo":{"@type":"ImageObject","url":"https://www.duocircle.com/images/duocircle-logo.png"},"description":"DuoCircle is a portfolio of specialized email products covering protection, authentication, delivery, and routing. We deliver about 90% of category-leader capability at roughly half the price, backed by experts who own the outcome. 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