SMTP Relay

What Does SMTP Relay Mean?

A simple mail transfer protocol relay (SMTP relay) is a service that is used as a means to transport email messages in between different email hosting services, servers and/or domains.

Techopedia Explains SMTP Relay

An SMTP relay is primarily used when an email needs to be delivered to a domain different from the user’s domain. For example, if an email is being sent from [email protected] to [email protected], SMTP relay is required to transmit messages between each domain. SMTP relay is generally a third-party application or service that mediates the process of sending, delivering and fetching email messages between different email hosts.

SMTP relays are also used in email composing applications such as Outlook. Users can configure their email address on the software and are able to send emails from multiple email addresses (of the same or a different domain) without the need to consider domain, ISP or organization.

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Margaret Rouse

Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.

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