IIS SMTP relay service

Posted by Vivid_Mongoose_8964@reddit | sysadmin | View on Reddit | 4 comments

So I've got the smtp virtual server setup to relay to o365, no issues when relaying mail internally on [xyz.com](https://xyz.com) with copiers, however I can't send emails from a copier to [gmail.com](https://gmail.com) or any other domains. I've added \*.com and [gmail.com](https://gmail.com) as remote domains, and told them to use smarthost [mycompany-com.mail.protection.outlook.com](https://mycompany-com.mail.protection.outlook.com) but nothing still. any ideas on what the holdup could be? i see nothing in the mailroot log files either, ty

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4 Comments

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lechango@reddit

Make sure you've got the public/WAN IP the copier is sending out of in a connector in Exchange Admin, also a good idea to add that IP to the SPF record for your domain. When you are using the O365 smarthost/relay the copier is acting as the first hop mail server, so it needs to be allowed accordingly.

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Vivid_Mongoose_8964@reddit (OP)

copiers connect to the onprem smtp virtual server, that connects to 365. all of that is fine and works great for internal mails

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lechango@reddit

Ah I see, I missed that part of it connecting to the onprem server first, sounded like you were pointing the copier straight to the O365 smarthost on first read. Maybe see if you can send a test mail to learndmarc.com from the copier and see if it picks it up and can identify an SPF alignment issue or similar.

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Vivid_Mongoose_8964@reddit (OP)

This is my issue, pretty common it seems [https://answers.microsoft.com/en-us/outlook\_com/forum/all/configuring-office-365-smtp-mail-relay-for/c0bbb6d4-a3c5-461b-811d-85de21a7090b](https://answers.microsoft.com/en-us/outlook_com/forum/all/configuring-office-365-smtp-mail-relay-for/c0bbb6d4-a3c5-461b-811d-85de21a7090b)