Automatic replies only to emails outside the organization?

Michal Rama 40 Reputation points
2026-06-26T11:38:14.2066667+00:00

Hello,

I need to set up automatic replies for a shared mailbox. However, only for external emails, it doesn't matter for emails within the organization.

There is an option for automatic forwarding in the Admin Center. I can even set it to send a completely different message. However, I don't see anywhere an option to not send anything at all within the organization.

Please help

Thank you

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2 answers

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  1. Anonymous
    2026-06-26T12:55:45.3566667+00:00

    Hello @Michal Rama

    You can try using Exchange PowerShell like below:

    Set-MailboxAutoReplyConfiguration 
    -Identity ******@domain.com 
    -AutoReplyState Enabled 
    -ExternalMessage "External auto-reply message." 
    -ExternalAudience All
    

    This is the closest supported behavior to sending automatic replies only to external senders.

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  2. Aniket Gharat 0 Reputation points
    2026-06-26T12:05:27.2566667+00:00

    Outlook does not allow autoreply exclusively for external users. However you can Use Power Automate for auto reply. Works perfectly for shared mailboxes and gives you full control over external vs internal filtering.

    Steps

    Go to Power Automate (https://make.powerautomate.com)

    Create → Automated Cloud Flow

    1. Trigger: When a new email arrives in a shared mailbox (V3)

    Add Condition: Check if sender is external

    Example expression: not(endsWith(triggerOutputs()?['body/from/emailAddress/address'], '@yourcompany.com'))

    1. If YES (external sender): Add action: Send email from shared mailbox (V2)
      • To: triggerOutputs()?['body/from/emailAddress/address']
      • Subject: RE: @{triggerOutputs()?['body/subject']}
      • Body: Thank you for your email. We will get back to you shortly.

    Advantages

    • Works even when no one opens Outlook
    • Fully controlled logic (domain-based filtering)
    • No dependency on desktop
    • Audit + maintainable (important for enterprise)

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