Send only server


I’m trying to use MIAB as a “send only” mail server.
There’s another mail server under the same domain, and this other mail server has an MX record.
MIAB host does not.
Unfortunately, if I try to send a message from MIAB host to an address in that domain, it gives me an error “Recipient address rejected: User unknown in virtual mailbox table”.

Is there a way to force it to send the message to the server under the MX record, if there’s no such mailbox on MIAB host?


Does anyone know how to do this? Please, help.

If you want to use MIAB installed on your VPS instance to send email to your Google Gmail account but your SPF, DKIM, and DMARC are not configured properly then Gmail is going to reject your email. Also, please configure your domain to use your VPS instance as your mail server. This means you MUST set the MX record or you cannot receive email.

My suggestion would be to setup your mailinabox up on a subdomain for example if your domain is example(.)com with another provider, you could setup box(.)mail(.)example(.)com as the domain. Then, when you try to send to something@example(.)com, it won’t think itself is authoritative for that domains mail.

Barring this, if you’re just wanting to setup basic relaying and you don’t mind a bit of manual config, you could just setup postfix to relay emails as this is fairly easy.

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