Issue Postfix/SMTP problem

[Edward Dekker]

Hello everybody,

I have a situation by my Postfix/SMTP.

When i want to use a SMTP-connection do i have some problems. My SMTP of my server tells that i have go to smtp.smtp.<domain.com>. And also my webmail fails when i want to send a message. Showing a error with code 250.

I want to set my server to smtp.<domain.com>. How could i adjust this to the correct settings?

 

[Edward Dekker]

Tonight i have discoverd that the problem comes when the Open Relay are closed or opened into the Plesk Onyx panel. And you want to send a message by Postfix.

When Open Relay: smtp.<domain> - mail.<domain> will works.
By Closed Relay: smtp.smtp.<domain> and/or <domain> are the only solution. And the webmail are not working to send a message..

Seems to be an flaw by the configuration settings of Plesk.

-----------------------------------------------------------------------------------------------------------------
Product version: Plesk Onyx 17.8.11
Build date: 2018/09/20 15:00
OS version: CentOS 7.5.1804
Revision: c3fb546fb867ac424d65da14d8b023f11ec0d150
Architecture: 64-bit
Wrapper version: 1.2

 

[Bitpalast]

This analysis cannot be correct, because open relay or authentication requirement does not interact with subdomain names at all. The SMTP server name should not be smtp.<domain.com>, but <hostname>. For example, if your host is named "myhost.mydomain.com", then the correct SMTP server setting is "myhost.mydomain.com", nothing else. There is only one single hostname for all domain accounts on the same machine. This one hostname is equipped (can be fitted) with an SSL certificate that is made out to that hostname, not to smtp.<domain.com>. You will always have problems when not using the correct hostname.

I wonder where you see that the SMTP server says, it wants to be addressed as smtp.smtp.<domain.com>. Could it be possible that you have named your host "smtp.<domain.com>"?

 

[learning_curve]

As @Peter Debik has said really, but FWIW, the image shows the setup we use, together with a Let's Encrypt *Wildcard & Multi-Domain SSL (which includes cover for the FQDN used for the server / mail server / Plesk panel etc) and this works perfectly, without any issues at all, on e-mails from all domains that we're hosting.

 

[Edward Dekker]

Thanks @Peter Debik for your post.

As before i suggested the double smtp subdomain occurring into a machine when the open relay are closed and the fqdn are not fully specified at the host and using EmClient on a workstation.

I've not tested the other situation when a server are specified according by the fqdn rules like server1.example.com.

Best regards,
Edward