Technicall possible, but not in Plesk GUI.

Any further development regarding smarthost functionality is welcome.

In today's world, this is mission critical and expected. The feature is built right into Mailenable which is where I keep having to set it up. It shouldn't take much work to get this integrated into Plesk for Windows installations. The settings can be set via powershell via the Add-PSSnapin MailEnable.Provision.Command to change the values on the poSmarthostOutboundEnabled settings. OR these settings can be modified by changing the values in the POSTOFFICE.SYS file within ~\Mail Enable\Config\Postoffices\(POSTOFFICE TO CHANGE). If you modify the file directly you may need to tell the services to restart, but I'm not sure.

By now, only a postfix hack under the hood makes it possible via sender_dependent_default_transport map to achieve this goal.

We have several customers on several plesk servers that need to route the traffic for specific domains to a mail encryption gateway for example. Others need to route to M365 Tenants to have a kind of Hybrid-Setup with M365 Exchange and classical IMAP accounts.

One of our solutions is the swiss mail encryption vendor SeppMail. They are able to route the traffic for a domain based on wheather the mail is been sent or received through the gateway.

It should be nice when their is an choice to send with smarthost or server per domain. Most problems i have is when site and mail are not on the ssme server

Yes, this will be very helpful. There is definitely a big issue with this for cases like ours - we have several domains in Plesk and one of them is hosted on GMail. So for this one we would like to setup a GMail relay using the smarthost functionality. With the current state of the smarthost feature, this effectively breaks all other domains that send mail through the local SMTP server. As you may know - setting up app passwords on GMail accounts is getting phased out, so it is not possible to use a GMail account authentication on the smarthost (they all have 2FA, as you can imagine). So the only option is to leave the smarthost without auth and to restrict it on the GMail side by IP. Again - this doesn't work as it directs all domains through the GMail SMTP, which on it's side rejects the domains that are not registered on out Workspace account. A very, very common case, I beleive. Limiting which domains should use the smarthost and which should send directly will solve this it seems. It would be better to have a dedicated smarthost per domain, but since it is technically challenging, the proposed solution will be far better than nothing.

It's very important. Thank you so much for open voting.

Thanks for starting a second suggestion/vote. I can't think of a case where we'd want to do this only at the server level and not per domain.

That would be really helpful to make the server send all e-mails through Exchange (Online) infrastructure to apply company policies and DKIM, for example.

es necesario

I would like the reverse. It would be very useful to have plesk as the in and outbound relay for exchange inc DKIM if that is possible. Bit like a proxy.

very interesting!

Add a feature that allows the configuration of Postfix relay to Exchange for a specific domain.

For example, all outgoing emails from @example.com are relayed to an Exchange/Office 365 server.