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Mailing List Bounce Management

Mailing list owners may need to perform some list maintenance in order to manage bouncing subscribers. The following information will help list owners understand Sympa bounce management and provide instructions on routine maintenance of bouncing subscribers.

What is a bouncing address?

If the Sympa list server sends a message to a mailing list and receives a non-delivery notice when trying to send to a subscriber's email address, the subscriber will be classified as bouncing. The bouncing subscriber is not removed from the mailing list, and Sympa will continue to try to send each list message to a bouncing subscriber.

What causes email messages to bounce?

Permanent mail bounces will not clear up by themselves. List owners need to correct these problems. An example of a permanent failure is an incorrect or non-existent subscriber email address. If you discover that a mail bounce is permanent, you might want to remove the subscriber from the list or contact them to find out their correct email address.

Temporary mail bounces will clear up after some action is taken. List owners may need to notify the subscriber or the Listmaster if the problem persists. Examples of temporary failures include a subscriber being over their mailbox quota, or when some sort of larger outage makes mail temporarily undeliverable to a group of users. Ten days after the temporary mail delivery issue is resolved, the Sympa list server will remove the bounce information.

How do I find out why a subscriber on my mailing list is bouncing?

Log on to the mailing list server at Click on the (Admin) link next to your mailing list name, and then click on the Review Bouncing Addresses link in the List Administration section. While on the Review Bouncing Addresses page, you can click on a specific email address to get more information, including the time period during which messages bounced, the number of messages that bounced and a copy of the last bounced message.

Why are subscribers on my mailing list still bouncing when I know the temporary mail delivery issue has been resolved?

Subscribers might have had a list message bounce due to some temporary mail delivery problem. Even if just one message bounces, Sympa will classify the subscriber as bouncing and Sympa will retain that bouncing status for 10 days after messages are again being delivered successfully. During these 10 days, the subscriber will still be classified as bouncing and the list owner will continue to receive warning messages about bouncing subscribers.

How can I reset the bounce status for list subscribers?

If a temporary bounce issue has been resolved, list owners may want to click the “Reset Bounce Errors” button so that a subscriber is no longer designated as bouncing. Doing this will not remove the subscriber from the mailing list.