If SPF fails or softfail then mark/deliver email to spam folder in email clients

[poetry]

Hello,
Is it possible to configure Proxmox Mail Gateway 6.1-3 to mark/deliver email that fails SPF to spam folder in email clients?

Is there any kind of protocol that would make this possible. Just thinking out loud. If this is not possible can you somehow configure some rule to mark spam messages in some other way?

We are getting targeted by a lot of spam and almost always there is SPF fail or softfail on messages that are spam. Sometimes there is also SPF_NONE. If we try to increase the spam score then we are also going to block a lot of costumers that do not have their email servers setup properly so there is always a trade off when blocking spam...

Any advice would be appreciated.

 

[Stoiko Ivanov]

Is it possible to configure Proxmox Mail Gateway 6.1-3 to mark/deliver email that fails SPF to spam folder in email clients?

You can use the Modify spam subject action - this adds a '[SPAM]' in front of the subject - you can use this in the mail-client to save the mail to the spam folder. Depending on your mailserver and if it supports it - sieve-filter has the advantage of running on the server - thus it is not dependent on the client with which you access your mails (e.g. thunderbird vs. mobile phone vs. webmail).

We are getting targeted by a lot of spam and almost always there is SPF fail or softfail on messages that are spam. Sometimes there is also SPF_NONE.

for the hard SPF fails you can simply enable the 'Use SPF' in the GUI->Configuration->Mail Proxy->Options - that way those mails will get rejected during the SMTP session.

If we try to increase the spam score then we are also going to block a lot of costumers that do not have their email servers setup properly so there is always a trade off when blocking spam...

This is the central problem here - SPF by itself is not a good measure if something is spam or not.
Check the spam-mails and your mail logs which spamassassin rules hit for the spammails and maybe you'll find a pattern and a good selection of rules where you can increase the spamscore.

Check also if you have URIBL_BLOCKED hits - this usually indicates that your PMG does not get answers from URIBL - which results in far worse spamdetection - see https://cwiki.apache.org/confluence/display/SPAMASSASSIN/DnsBlocklists

I hope this helps!