Use the following "quarantine spam" filter to decrease the number of spam messages
directed to a recipient's mailbox. The "quarantine spam" filter is a modification to the
default policy script filter found in "Policy Script 6: Calculate Spam Probability, Modify and
Deliver". Unlike the default policy script filter, the "quarantine spam" filter
quarantines messages when the spam probability is over 80%. (The default policy filter only
"files" spam messages when the spam probability is over 50%. See the
pmx_file command in the pmx-policy manpage.
# attr NAME=quarantine spam
# Quarantines spam if probability over 80%.
# Else, delivers message if probability over 50%.
# Prefixes "Subject" header with "[SPAM:]".
# Adds an "X-PMX-Spam" header.
if pmx_spam_prob :over 80 {
pmx_quarantine "Spam";
stop;
}
elsif pmx_spam_prob :over 50 {
pmx_replace_header "Subject" "[SPAM:%%GAUGE%%] %%SUBJECT%%";
pmx_add_header "X-PMX-Spam" "Probability=%%PROB%%";
}
Description:
- If the pmx_spam_prob test finds the message has a spam probability of 80%
or more:
- The pmx_quarantine action copies the message to the PureMessage quarantine with the reason "Spam". This
string should be a single word. If multiple words are used the spaces between the words are
silently changed to underscores. For example, the string "message is spam" becomes
"message_is_spam". Quarantined messages can be viewed, released and digested using the
PureMessage Manager and the quarantine tools.
- The stop command then ends message processing.
- If the pmx_spam_prob test finds the message has a spam probability of 50%
or more:
- The pmx_replace_header action prefixes the "Subject" of the message
with a string similar to: "
[SPAM:###]
", where each additional "#" character denotes 10% above the argument to
pmx_spam_prob (at least one '#' is always appended, indicating that the
message contains 0-50% spam).
- The pmx_add_header action then adds an "X-PMX-Spam" header to
indicate the message's complete spam probability.
Where does this filter go?
The "quarantine spam" filter replaces the filter found in "Policy Script 6: Calculate
Spam Probability, Modify and Deliver". Replacing this default policy filter with the
"quarantine spam" filter ensures that:
- The "quarantine spam" filter executes when messages from external hosts have spam
probabilities of either over 80% or over 50%.
- Messages with a spam probability of 80% or more are quarantined.
- Messages are delivered, with additional headers, to envelope recipients if the spam
probability is between 50% and 79%.