Large-Scale Mail with Postfix, OpenLDAP and Courier
Most of the administration tasks, such as adding, modifying and deleting accounts and aliases, require modifying the LDAP directory. You can do this with the OpenLDAP command-line tools or a generic LDAP browser like gq. These methods are cumbersome, however, because they are generic tools and are not tailored to the task of administering e-mail accounts. We've been working on a web administration application called Jamm that is essentially an application-specific LDAP browser written in Java and JSP. It also has its own LDAP schema that is a slightly modified Courier schema. Jamm is currently usable and is constantly evolving. Visit the Jamm web page on SourceForge for the latest Jamm information.
When you create an account or an alias inside the LDAP database it will instantly become active as far as the mail system is concerned. For virtual accounts, note that the UNIX directory in ~vmail is not created at this time. However, we can work around this because Postfix's virtual delivery agent will create the necessary directories the first time it has to deliver mail. Due to this fact, we recommend sending a welcome e-mail as soon as you create the account.
When you delete an account or an alias in the LDAP database, it will instantly become inactive. For virtual accounts, note that the UNIX filesystem isn't cleaned up. In other words, the data remains on disk until a system administrator can remove it. This allows you to keep the data from dead accounts for a grace period in case the account was deleted in error. However, if another account is created with the same name and the same mail path, the data will be available to the new account. This could be considered a privacy violation for the previous user.