Question Postfix - How to not resolve mail internally?

[Faustino50]

Server operating system version

Ubuntu 18.04

Plesk version and microupdate number

Obsidian

Hi Plesk's members,
I have a problem that I do not know how to solve, I tried to search on Google and here but nothing to do.

Now I have this situation:
* Customer with a domain (e.g. faustino50.xyz)
* This customer has a mail server with a third party solution (e.g. GMail or Outlook or something else)
* This customer want a server mail for the newsletter, so we have activated a server with Plesk to handle the mail
* On this server there is only 1 account, "newsletter@faustino50.xyz"
* When I have to send a mail to "ceo@faustino50.xyz" from this server, Plesk/Postfix tries to search that address internally and not externally throught MX record, GMail/Outlook, ...
* So I receive the error "Recipient address rejected: User unknown in local recipient table" and do not send the mail / newsletter

How can I have to say to Plesk or Postfix that "faustino50.xyz" have to resolve externally and not internally?

 

[Monty]

You can't have 2 mail servers being responsible for the same domain, this will in most cases break things. The postfix tables take precedence over DNS records, so if your domain is a "local" mail domain then locally sent mails will always be delivered locally.

In theory, you could work around this by applying some manual modifications and transport tables to Postfix but I wouldn't recommend this.

An easier solution may be:

• Disable mail services for your domain faustino50.xyz in Plesk (so that Plesk does not consider this domain a local mail domain)
• Create a subdomain such as newsletter.faustino50.xyz
• Enable mail services on this subdomain
• Configure your newsletter software to send/receive mails with the @newsletter.faustino50.xyz domain