PureMessage for UNIX: quarantining backscatter/NDR messages for selected recipients

  • Article ID: 37260
  • Updated: 17 Dec 2008

If some of your email users are receiving backscatter spam messages, you can use the PureMessage policy to quarantine this type of message for the recipients for whom this is a problem.

First you must create a policy list that will contain the email addresses of recipients whose backscatter messages you want to quarantine. Then you add a rule to the policy that quarantines messages for this reason. Optionally, you can also deliver quarantine digest notifications to list members via email.

Note: Messages that are rejected by the receiving mail transfer agent (MTA) during the initial SMTP transaction cause a notification to be delivered to the original sender, which does not result in backscatter.

1. Create a new policy list

  1. On the Policy tab, next to the Lists heading, click New.
  2. Ensure that the Type is set to List. Then enter the following values for the new list:
    • ID: backscatter-NDR
    • Name: Backscatter quarantine opt-ins
    • Description: quarantines backscatter/NDR messages for list members.
  3. In the Match Type list box, select Email Globs.
  4. Click Save. A message is displayed, indicating that the list has been created.
  5. Click here to add email addresses to the list now, or click OK to continue and enter the addresses later.

2. Add a new policy rule

  1. On the Policy tab, in the top right corner of the Policy: Rules page, click see the source. The PureMessage policy is displayed as Sieve code.
  2. Click the /opt/pmx/etc/policy.siv.edit link to access the raw, editable code.
  3. Copy and paste the backscatter/NDR rule into the Manager in the place in the policy that is shown below (the backscatter rule is displayed in bold type).
      # attr NAME=Copy to quarantine and deliver if spam probability is 50% or more
    if not pmx_spam_prob :under 50 {
    pmx_replace_header :index 0 "X-PMX-Spam" "Gauge=%%XGAUGE%%%%IGAUGE%%, Probability=%%PROB%%, Report='%%HITS%%'";
    pmx_mark "pmx_reason" "Spam";
    pmx_file "Spam";
    pmx_replace_header :index 0 "Subject" "[SPAM:%%GAUGE%%] %%SUBJECT%%";
    # attr NAME=Quarantine Backscatter/NDR messages
    if allof(pmx_spam_hit :comparator "i;ascii-casemap" :contains ["BOUNCE_ENVELOPE"],
    address :all :memberof :comparator "i;ascii-casemap" ["to", "cc","bcc"]
    pmx_quarantine "Backscatter";
    pmx_mark1 "Backscatter";

    # attr NAME=Add X-Header and deliver messages
    else {
    pmx_mark "pmx_reason" "Legitimate";
    pmx_replace_header :index 0 "X-PMX-Spam" "Gauge=%%XGAUGE%%%%IGAUGE%%, Probability=%%PROB%%, Report='%%HITS%%'";
  4. Click Save.

3. [Optional] Enable Digesting for Quarantined Messages

You may want to send quarantine digests to notify members of the Backscatter quarantine opt-ins list about messages that have been quarantined. This can be done by adding the reason "Backscatter" to an existing digest template or creating a new digest template that uses the reason "Backscatter." The reason must match the reason specified in the quarantine action for the backscatter rule. For more information about quarantine digests, see Managing Quarantine Digest Rules in the Manager Reference section of the PureMessage documentation.

If you need more information or guidance, then please contact technical support.

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