Bypass Azure VM Port 25 limitation for internal communicaton

Christopher Stainczyk 40 Reputation points
2023-10-06T12:36:56.25+00:00

Hello community!

I know from here: https://learn.microsoft.com/en-us/azure/virtual-network/troubleshoot-outbound-smtp-connectivity thats it's not possible to open port 25 outbound from a azure vm if your are not having a enterprise agreement. We need to send mail from a azure vm to exchange online (company.mail.protection.outlook.com)

I know it's a bit optimistic but is there maybe any way to have a "direct" route from a azure vm to exo and use port 25? Problem is that smtp.office365.com over 587 is not possible, because we cannot use smtp authentication. We have to use TLS oder IP-based authentication. This could be done by using a third party smtp relay, but it would we much nicer if the mails don't "leave" azure.

Thank you and have a good day

Chris

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  1. Michael Durkan 12,156 Reputation points MVP
    2023-10-07T12:40:04.63+00:00

    Hi

    see similar thread on this query here:

    https://learn.microsoft.com/en-us/answers/questions/1358541/how-to-fix-smtp-relay-issue-on-azure-vm?wt.mc_id=AZ-MVP-5005255

    SendGrid may be an option for you instead as it accepts unencrypted and TLS connections

    Hope this helps,

    Thanks

    Michael Durkan

    • If the reply was helpful please upvote and/or accept as answer as this helps others in the community with similar questions. Thanks!
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