Supported SMTP/ESMTP Commands and Extensions

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Updated:May 26, 2021
Document ID:217162

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    Introduction

    This document describes the available SMTP/ESMTP commands and extensions on the Secure Email Gateway (formerly known as the Email Security Appliance). If a command or extension is not listed here, or if you wish to obtain additional details, please reach out to Cisco TAC.

    Commands

    These are a few available commands on Secure Email Gateway:

    • DATA
    • EHLO
    • HELO
    • HELP
    • MAIL FROM
    • NOOP
    • QUIT
    • RCPT TO
    • RSET
    • VRFY

    Extensions

    Listed here are a few available extensions on Secure Email Gateway:

    • 8BITMIME
    • AUTH
    • SIZE
    • SMTPUTF8 (AsyncOS 14.0 and newer)
    • STARTTLS

    Related Information

    TAC Authored

    Contributed by Cisco Engineers

    • Dennis McCabe Jr
      Cisco TAC Engineer

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