When is a User Sieve Script activated? Before or After Spam-Filtering?

Questions
1

Your question

I have an account that has a User Sieve script assigned that matches “*” and forwards all mail received to a different mail server. I’m trying to determine if this Sieve script is activated and run before or after the mail is processed by the Spam-Filter process?

I understand that topics in this category are triaged by a bot first but a human reply will follow up. If I’d prefer a human-only reply, I’ll add the no-ai tag to my topic.

on

2

Order is: SMTP DATA (spam filter runs here, can reject) → message
accepted to the queue → per-recipient delivery → per-user sieve.
So a “forward everything” user script does run on messages that the
spam filter scored but didn’t reject (e.g. flagged-as-spam but
accepted).

If you want to skip spam in the script, guard the redirect:

require ["spamtest", "comparator-i;ascii-numeric"];
if not spamtest :value "ge" :comparator "i;ascii-numeric" "5" {
    redirect "[email protected]";
}

spamtest returns the numeric spam score at delivery (the verdict
is attached before the user script runs). Alternatively raise the
spam-filter rejection threshold so accepted-spam never reaches the
script in the first place.

3

Does this mean, the SpamStatus and SpamScore headers are visible to Sieve scripts a user defines (example in Roundcube)?

4

The spam score and tags are visible as headers but not the final result. To access the final result you need to use the spamtest function.

5

Thank you. This is helpful to understand.