In my organization it is impossible to know the password for each and every mailbox, what shall i do?
If you are using a LDAP server that can supports multiple attribute for the password such as Sun LDAP then simply you can add an extra attribute “userPassword” with a standard password as the value on all of the user accounts, as a result each useraccount will be having his/her own password and another password that is known by the you and that you can use in the migration file. became an easy task now to add this standard password in the migration file!!!