How to find unused distribution groups

The problem

Distribution groups (DLs) are an essential feature of any messaging system. They enable you to send a message to a group of users without having to worry about selecting them one by one. There are two types, depending on how they are managed.

Administrator-managed groups

These are designed to adapt to the company's structure and are generally maintenance-free. Most of the time, they are dynamic groups created by filtering on a directory attribute to encompass all mailboxes that have it in common; for example, all users in a service or department.

Because of the nature of these groups, the e-mail administrator is entirely autonomous in managing them.

User-initiated groups

Other groups are created as and when required by users, for example in the context of a particular project or event. Once the project or event is over, the group becomes useless, but it is rare for the user who requested its creation to ask for it to be deleted. A group can also be used as an alias to manage employee movements, or to provide an e-mail address accessible from the outside.

As an e-mail administrator, you therefore find yourself with user-initiated groups, either created by yourself or by your predecessor, and most of the time you have no idea what they are actually used for.

Deleting a user-initiated group is always a delicate matter, as it can incur the wrath of those who are still using it, if carried out indiscriminately. 

How to securely delete unneeded distribution groups?

In a series of articles illustrating the use of Promodag Reports, we take you through the various steps involved in securely deleting your unneeded distribution groups.

1. List groups that have not been used for a certain number of days

It is commonly accepted that a group can be considered unused if it has not received any emails for a certain period of time.
It is therefore necessary to determine a reasonable period of inactivity and list the groups that have not been used during this period, for example 90 days. Please note that this type of filtering requires your group usage history to reach at least 90 days. 
The method used is described in this article: List groups that have not been used for a certain number of days.

2. List the latest messages sent to these groups

From the list established in the previous step, it may be useful to have a history of the last messages received by the group. This can help the owner decide whether or not to delete the group. 
This article explains how to proceed: List the last messages sent to distribution groups. 

3. List groups with no members

Groups with no members are also good candidates for deletion, as they are unlikely to serve any purpose. You can therefore add them to the list of groups that you will send to their owners to confirm their deletion.
The corresponding procedure is described here : List distribution groups with no members.

4. Retrieve the owner(s) of selected groups and their characteristics

Among the information required to decide whether to delete a group, the following may be useful: group name, email, creation date, number and list of members. And, of course, the name and e-mail address of the owner(s), who will be asked if the group can be deleted.
Here's how to create this list: List unused distribution groups, their characteristics and owners.

5. Send a message to group owners

All that's left to do is to send a message to the owners of each group detected as potentially unused thanks to the information collected in the previous steps:

• Group characteristics,
• Group type empty or unused for x days,
• Date last used and last message received.

All you have to do is wait for them to reply to confirm whether their groups can be deleted.

Of course, you can also choose to delete the groups in question without referring to the owner, either because he's no longer part of your organization, or because you don't wish to solicit him. Either way, you now have all the information you need to make a well-founded decision.