does the exchange server need internet to send emails to external receipents

pavan kumar 371 Reputation points


A question came up from my network team.

one of our internet line provider is doing some upgrade and my manager wants to make sure there is no imapact to the mail flow internally and externally (outbound).

My answer is - internet is not needed for exchange to send out email. correct me if i am wrong.

We have exchange servers on-prem.

our outbound mailflow looks like this.

exchange server > Email Gateway > to internet.


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2 answers

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  1. Andy David - MVP 143.8K Reputation points MVP

    How else does Exchange send to external recipients?
    If it uses that same connection that s being upgraded, then it could be impacted.

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  2. Joyce Shen - MSFT 16,646 Reputation points

    Hi @pavan kumar

    Agree with Andy, I'm afraid you will have trouble sending mails to external.

    You could also refer to the discussion in this related thread: How do you send an email within a network without internet?

    You will not able to send email from a source outside a network to a device inside a network when you've cut off the connection between the outside and inside.
    However, devices on an isolated network can send email to each other.

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