Port issue

Peter_1985 2,546 Reputation points

If relevant port (related to SMTP) is filtered, what adjustment can be adjusted within Win server?

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  1. Candy Luo 12,661 Reputation points Microsoft Vendor

    Hi ,

    Please clarify more details to help us understand your question.

    Did you mean relevant SMTP port is filtered on firewall/router and what port does windows server need to allow? Please feel free to let me know if I have any misunderstanding.

    When an email client or outgoing server is submitting an email to mail server, it should always use SMTP port 587 as the default port.

    Port 25 is the recommended port number for SMTP communications between mail servers (i.e., for relaying messages), port 587 is the one recommended for message submissions by mail clients to mail servers.

    On Mail server's windows firewall, you need to allow inbound traffic on port 587 and port 25. Please refer to the following picture:


    In addition, For SMTP related question is beyond our windows network support, it depends on which mail server you are using. If you are using exchange mail server, then you could ask the related question in our exchange forum. If you are using third-party mail server , you would better contact the vendor of mail server for better answers.

    Best Regards,


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  2. Peter_1985 2,546 Reputation points

    Yes, SMTP port (like 587) is filtered. What action can be taken to validate it and release any filter?

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