Question Limit the number of recipients for a single message on outgoing emails

[Patashoow]

Server operating system version

Ubuntu 22.04

Plesk version and microupdate number

18.0.66

Hi,
Is there a way to limit the number of recipients (To, CC and BCC) for a single message on outgoing emails with Plesk?
I'm using Postfix and all emails are sent through an external email server via SMTP.

Thanks for any help.

 

[MSandakov]

Unfortunately, you cannot adjust this restriction directly through Plesk.
However, you can use `smtpd_recipient_limit` in your Postfix configuration. To do this, add the following line in /etc/postfix/main.cf:

smtpd_recipient_limit = [number]

Then, restart the Postfix service:

systemctl restart postfix

This will cap the number of recipients allowed per message. Any message with more recipients than the specified limit will be rejected.

Keep in mind, it will apply to all domains on the server.
Additionally, this is not a standard Postfix configuration in Plesk and has not been tested before, so it may affect Plesk functionality. Please be cautious with changes in the postfix configuration.

 

[Patashoow]

Thank you for your reply. I don't know if I was able to explain well my situation but in fact, I'm using an external service for all my outgoing emails (an external SMTP relay) so maybe that this new information changes something?

I've read on the internet that even though Postfix is just a relay, I can still enforce limits at the relay level but will this interfere with Plesk or any other functionality?

 

[MSandakov]

so maybe that this new information changes something?

I don't think so, because emails will still be sent from the Plesk server and should comply with Postfix restrictions.

will this interfere with Plesk or any other functionality?

Potentially there might be issues with Plesk notifications if the recipient limit is set too low. However, I haven't had a chance to verify this yet. As I mentioned, this configuration hasn't been thoroughly tested because Plesk doesn't provide an option to set this restriction directly.
I don't personally think it will cause any issues unless the restriction is set very low (below 10). Additionally, you can disable this restriction at any time.