Question What would happen if I turned off/removed SMTP entirely in Plesk?

[Paul Larson]

Server operating system version

Ubuntu

Plesk version and microupdate number

18 Onyx

Most of my client domains either a) send PHP email from a contact form, or b) use a Transactional Service like Postmark to deliver email.

My server has no active email accounts.

Am I ok to turn off/remove SMTP completely? Would it have any repercussions I'm not thinking of?

I assume the standard Plesk SMTP services are more geared towards hosting proper email accounts that need to send. But with so much email responsibility in the cloud, I figured it's possible I could remove. (With the added benefit it would solve a security warning on our recent penetration test)

 

[Kaspar]

[....] Would it have any repercussions I'm not thinking of?

Yes! The SMTP server (Postfix) is used for the actual sending of all email. Which includes the mail send by PHP forms and notification send by Plesk. Removing/stopping/disabling SMTP will prohibit your server form sending ANY email.

 

[Paul Larson]

What about if I turned off POP/IMAP and left SMTP intact?

 

[Peter Debik]

Clients will stay able to login and submit mails to the MTA for transmission, but they will not be able to login to any mailbox for retrieving mail.

 

[Kaspar]

What about if I turned off POP/IMAP and left SMTP intact?

If your server has no mailboxes you could disable POP/IMAP service (Dovecot) or block the associated ports.

 

[Paul Larson]

Thanks! What should one even do in this situation (if a tech scan demands these mail services are removed?)

I think I read that Plesk can be configured to use an external SMTP server? And nerdier still, I suppose Transactional Services with an email/SMTP API could be used.

But I think it makes more sense to ask for a security exemption for the SMTP service. Just looking for opinions!