This tip looks at some of the possible causes of receiving a mailbox bounce -- a message from the recipient's mail server that the message could not be delivered. There are essentially three kinds of messages bounces that you might encounter. One resolves itself, one may require action on your part and one will almost certainly require your action.
Soft bounces can occur as a result of a problem with the ISP or a user's mailbox being full, or even a mailbox size limit set on the firewall. Soft bounces are the result of temporary problems that can be resolved in a short space of time.
Hard bounces can occur when an e-mail address is entered incorrectly or an employee has left a company and didn't forward mail to another mailbox. Depending on the situation, hard bounces can be resolved in a timely manner.
Mail bounce from a distribution list
If a mailbox that has been removed was a member of a distribution list, and mail was sent to that distribution list, the sender may receive a bounce pertaining to the deleted mailbox. In this instance, there is a possibility that the Message Transfer Agent didn't update its cached list of distribution list members. To resolve this issue you will need to stop and restart the Message Transfer Agent Service. If are using Exchange 5.5 SP2, then you would not have this problem.
Adesh Rampat has 10 years experience with network and IT administration. He is a member of the Association of Internet Professionals, the Institute for Network Professionals and the International Webmasters Association. He has also lectured extensively on a variety of topics.