What is an email server?


When you send an email, an email server is a software program that picks it up and delivers it to your subscribers’ inboxes.

There are two main types of email servers:

  1. Outgoing (mail transfer agent): This server authenticates, encodes, and sends the email to the recipient.
  2. Incoming (mail delivery agent): This server retrieves and stores emails in the recipient’s mailbox.

How does an email server work?

Email servers distribute emails using protocols that tell them where and how to direct emails.

Protocols can have various functions, such as:

  • Sending (SMTP) 
  • Accessing (IMAP, POP)
  • Authentication (SPF, DKIM, and DMARC)
  • Security (SMPTS, SPF, and S/MIME)
  • Synchronization (EAS)

Once you send an email, an outgoing email server will check the recipient’s domain name system (DNS) and translate it into an IP address the incoming server uses to deliver the message to the right destination.

Once the incoming server forwards your message to the recipient’s inbox, their inbox provider checks your IP address and sender reputation to decide whether to deliver the email and which folder to place it in.

The server will bounce the email if it runs into an issue, such as:

  • Downtime
  • A spelling error in the recipient’s email address
  • A full recipient inbox

Why are email servers important for email marketing?

Besides delivering your emails to a single address, email servers can distribute them to your entire email list or chosen customer segments in no time. For this reason, they’re key in making sure your email marketing initiatives have high deliverability.

With Klaviyo’s deliverability hub, you can monitor your email deliverability, evaluate your email performance, identify bottlenecks, and make changes to maintain a stellar sender reputation.

Klaviyo makes it easy to send email campaigns and flows to stay connected with your target audience. Sign up for Klaviyo and craft personalized messages that convert and fuel growth.

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