Question Also allow non-SSL SMTP Connections

[zwankie]

Hi there,

I hope someone can give me some guidance or solutions here.

Every few months we have clients (mostly iPhone users) have problems with their email accounts connections when their domain Let's Encrypt SSL Certificates update.
Specifically when the use SSL for POP/IMAP or SMTP.

The Plesk server running Dovecote and Postfix allows Non-SSL POP/IMAP connections but not Non-SSL SMTP.
It only allows SSL/TLS smtp connections on port 587.

How can this be changed/configured so we can solve this problem for the users permanently?
Either fixing iPhones/Mac or Plesk to resolve this.

A telnet to port 25 produces 500 5.5.2 Error: bad syntax

I tried these two but no luck with a solid solution yet:

Resolved - E-mail works, connection trough apps(Outlook, Spark, Gmail etc) not

Hi, Have an issue that I can't figure out. Own Plesk VPS at strato, e-mail works and I can log in via webmail or native e-mail on iPhone/iPad. Server is fully up to date and plesk obsidian 18.0.48 as well. Devcot/postfix runs on it. But now I wanted to use a slightly more advanced app through...

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Issue - Cannot verify server identity popup iPhone & webmail

Hello Since yesterday, suddenly, cannot verify server identity is poping up on iPhone users of all our server users. Similar goes to webmail, check attached please, Why it happened at its own? We did not change anything. OS CentOS Linux 7.8.2003 (Core) Product Plesk Obsidian Version 18.0.28...

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[Peter Debik]

This is likely not a Plesk issue as Plesk does support non-ssl connections on port 25. It is a must for the SMTP server anyway, because other mail servers on the internet may not be capable of ssl connections, so in inter-server-communication having the ability to communicate with other mail servers non-encrypted is essential.

For the iPhone issue we have a KB article: https://support.plesk.com/hc/en-us/articles/12377286818071

For the port-25 issue I am not sure what causes that, but my guess is that smtp_enforce_tls is set in the postfix configuration (see Postfix Configuration Parameters for details).

 

[zwankie]

Thanks for the prompt reply Peter.

I added the smtp_enforce_tls = no to postfix and will test that now.

The iPhone workaround is an option but an absolute headache for users who need to regularly need to do this.
I wish there was a better way.