8.8 Free and busy 853
Items” feature. Alternatively, you could also restore a copy of the mailbox
database to another server and recover the data from that copy.
Somewhat surprisingly, Exchange does not provide a way to audit the use of
Export-Mailbox command, so it is possible for an administrator to
select the mailbox of someone important (or interesting) and run a job to
export data without leaving any trace that they cannot erase quickly after-
wards. Apart from the log ﬁles that Exchange creates for every
operation, the only other trace that an administrator has accessed
someone’s mailbox is in event 1006 logged by the Exchange Migration
component (Figure 8.49). For this reason, it is important that you set out
clear guidelines as to when an administrator can use the
command in the same way that guidelines exist to permit other administra-
tor access to user mailboxes.
8.8 Free and busy
Free and busy data is the mechanism used by Exchange and its clients to
track the availability of users for meetings. All versions of Exchange prior
854 8.8 Free and busy
to Exchange 2007 store the data used by clients to calculate when users
are available in a public folder, but Exchange 2007 introduces the new
Availability Service to replace the need to hold data in a public folder in
favor of direct publication of free and busy data by Outlook 2007 clients
as properties of user mailboxes. However, it is going to take some time
before any organization is able to deploy Exchange 2007 everywhere, so
we will have to deal with the public folder-based implementation for
quite some time to come.
Outlook is responsible for updating the data in the public folder and
does so according to user-speciﬁc options as shown in Figure 8.50. The
default is for Outlook to connect and update free and busy data every 15
minutes and to publish 2 months of availability data. In other words, if
every user in the organization uses the default publication options, you will
not be able to see the availability of another user’s calendar past the next 2
months, even if they have scheduled meetings and other appointments past
that time. You can publish a maximum of 36 months free and busy data
and update the server as often as every minute.
Free and busy data describes when a user is busy over a period of time
but does not hold any other information, such as whether they are at a
meeting or have a personal appointment, the location, or any other indica-
tion of why they might be busy. Thus, when you view another user’s calen-
dar and see that they are busy between 10
AM and 5PM, the time might be
taken up by one long appointment or occupied by several shorter meetings.
In addition, the items in the other user’s calendars may have different status
such as busy or tentative. Essentially, Exchange treats any slot that a user
creates in their calendar as busy and any that is vacant as free.