Bounces Management Settings

List owners receive a message when a message is distributed and this percentage is exceeded. In this case, if 30% of email bounces to the subscribers.

warn rate = when the percentage of bounced email from list members exceeds this value, then the list owner will receive a warning about the bounces exceeding the set value.

halt rate = when the percentage of bounced email from list members exceeds this value, then message for the list will be halted.

Bounce Score, Thresholds and Notification Settings

The threshold setting below is based on a bounce score. The bounce score = bounce_count * type_rate * regularity_rate

bounce count – number of bounced messages
type rate – type of bounce e.g. mail box full (temp 4.4.4 error codes) vs. permanent error (5.x.x. user not found)
regularity rate – the message count data, how many bounces occurred.

The bounce logic runs once a week. At that time server will automatically remove users from the bounce list that stop bouncing and continue to aggregate data for those that continue to bounce. Once a threshold is achieved, the server will remove the bouncing email address from the subscribers list.

Management of bouncers, 1st level

This setting defines automatic bounce behavior per user. In this case, if a user bounces 45 times, the server will send a notification to the subscriber and owner.

Management of bouncers, 2nd level

This setting defines the automatic behavior of the server for users that chronically bounce. In this case, after 75 bounces the subscriber is removed from the list and the owner is notified.

The settings are similar to 1st level management however, the threshold and actions differ. For example, this configuration tells the server to automatically remove the bouncing users from the mail list when the threshold reaches 75. These are the default settings for the server.

Percentage of list members in VERP mode

Defines the Variable Envelop Return Path (VERP) the percentage setting determines how many members of the list will get a VERP encoding. It encodes the subscriber email address in the return path so Sympa can track bouncing email to assist with automated bounce management.

VERP is expensive on the server’s processing time so in this case only 10% of the subscribers will get a VERP encoding, however, after 10 messages sent to the list then all subscribers will be tracked.

Message tracking feature

Enables message tracking on a per user basis.

Welcome return-path

The welcome message is sent to new users and if it bounces, then that address is removed from the subscriber list.

owner – the owner will receive a notification about the welcome message bounce for user X.
bounce management – the server to immediately remove an email address that bounces when the initial welcome message is sent to a new user.

Return-path of the REMIND command

Similar to the behavior of the “Welcome return-path” however this event is triggered by the subscription reminder message which is defined by the owner. Sympa sends a reminder email to list members reminding them about their subscription.