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ETRN

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Last Updated May 24, 2021 7:42 am

Short for Extended Turn, an extension to the SMTP mail delivery protocol that allows an SMTP server to request from another SMTP server any e-mail messages it has for a specific domain. ETRN typically is used to retrieve e-mail messages from a mail server that does not have a dedicated connection to the Internet.

ETRN can only be used in conjunction with an ISP that supports ETRN.