Administrator audit logging in Exchange Server
You can use administrator audit logging in Exchange Server to log when a user or administrator makes a change in your organization. By keeping a log of the changes, you can trace changes to the person who made the change, augment your change logs with detailed records of the change as it was implemented, comply with regulatory requirements and requests for discovery, and more.
By default, administrator audit logging is enabled in new installations of Exchange Server.
What gets audited
Cmdlets that are run directly in the Exchange Management Shell are audited. In addition, operations performed using the Exchange admin center (EAC) are also logged because those operations run cmdlets in the background.
Cmdlets, regardless of where they're run, are audited if a cmdlet is on the cmdlet auditing list and one or more parameters on that cmdlet are on the parameter auditing list. Audit logging is intended to show what actions have been taken to modify objects in an Exchange organization rather than what objects have been viewed.
A cmdlet might not be logged if an error occurs before the cmdlet calls the Admin Audit Log cmdlet extension agent. If an error occurs after the Admin Audit Log agent is called, the cmdlet is logged along with the associated error. For more information, see the Admin Audit Log agent section later in this topic.
Changes to the audit log configuration are refreshed every 60 minutes on computers that have the Exchange Management Shell open at the time a configuration change is made. If you want to apply the changes immediately, close and then open the Exchange Management Shell again on each computer.
A command may take up to 15 minutes after it's run to appear in audit log search results. This is because audit log entries must be indexed before they can be searched. If a command doesn't appear in the administrator audit log, wait a few minutes and run the search again.
Admin audit logging configuration
By default, when admin audit logging is enabled, a log entry is created every time any cmdlet is run. If you don't want to audit every cmdlet that's run, you can configure audit logging to audit only the cmdlets and parameters you're interested in. You configure audit logging with the Set-AdminAuditLogConfig cmdlet. The parameters referenced in the following sections are used with this cmdlet.
Changes to the administrator audit log configuration are always logged, regardless of whether the Set-AdminAuditLogConfig cmdlet is included in the list of cmdlets being audited or whether audit logging is enabled or disabled.
When a command is run, Exchange inspects the cmdlet that was used. If the cmdlet that was run matches any of the cmdlets provided with the AdminAuditLogCmdlets parameter, Exchange then checks the parameters specified in the AdminAuditLogParameters parameter. If at least one or more parameters from the parameters list are matched, Exchange logs the cmdlet that was run. The following sections contain more information about each aspect of the audit logging configuration.
For more information about managing audit logging configuration, see Manage administrator audit logging.
You can control which cmdlets are audited by providing a list of cmdlets, and their parameters, that you want to log. When you configure audit logging, you can specify to audit every cmdlet, or you can specify the cmdlets you want to audit by using the AdminAuditLogCmdlets parameter. You can specify full cmdlet names, such as New-Mailbox, or you can specify partial cmdlet names and enclose those names in wildcard characters, such as an asterisk (
*). For example, if you want to log when any cmdlet that contains the string
Transport runs, you can specify a value of
*Transport*. You can use a mix of full cmdlet names and partial cmdlet names at the same time to tailor the audit logging configuration to your needs.
To audit all cmdlets, specify only the wildcard character (*). This is the default setting.
In addition to specifying which cmdlets you want to log, you can also indicate that cmdlets should only be logged if certain parameters on those cmdlets are used. Use the AdminAuditLogParameters parameter to specify which parameters should be logged. As with cmdlets, you can specify full parameter names, such as
Database, or partial parameter names enclosed in wildcard characters (
*), such as
*Address*, or a combination of both.
To audit all parameters, specify only the wildcard character (*). This is the default setting.
Admin audit log age limit
By default, admin audit logging is configured to store audit log entries for 90 days. After 90 days, the audit log entry is deleted. You can change the audit log age limit using the AdminAuditLogAgeLimit parameter. For example, to change the age limit to 180 days, use the command
Set-AdminAuditLogConfig -AdminAuditLogAgeLimit 180. You can also specify the number of days, hours, minutes, and seconds that audit log entries should be kept. To specify a value, use the format
dd.hh:mm:ss where the following applies:
dd: The number of days to keep the audit log entry.
hh: The number of hours to keep the audit log entry.
mm: The number of minutes to keep the audit log entry.
ss: The number of seconds to keep the audit log entry.
You need to specify multiple years by using the
dd field. For example, 365 days equals one year; 730 days equals two years; 913 days equals two years and six months. For example, to set the audit log age limit to two years and six months, use the value
You can set the admin audit log age limit to a value that's less than the current age limit. If you do this, any audit log entry whose age exceeds the new age limit is deleted.
If you set the age limit to 0, Exchange deletes all the entries in the audit log.
We recommend that you assign permissions to configure the audit log age limit only to highly trusted users.
By default, the admin audit log records only the cmdlet name, cmdlet parameters (and values specified), the object that was modified, who ran the cmdlet, when the cmdlet was run, and on what server the cmdlet was run. The admin audit log doesn't log what properties were modified on the object. If you want the admin audit log to also include the properties of the object that were modified, you can enable verbose logging by setting the LogLevel parameter to
Verbose. When you enable verbose logging, in addition to the information logged by default, the properties modified on an object, including their old and new values, are included in the admin audit log.
Cmdlets that begin with the verb Test aren't logged by default. You can indicate that Test cmdlets should be logged by setting the TestCmdletLoggingEnabled parameter to
$true. Although you can enable logging of test cmdlets, we recommend that you do this only for short periods of time because test cmdlets can produce a large number of audit log entries.
Admin audit log
Each time a cmdlet is logged, an admin audit log entry is created. The audit log entries are stored in the admin audit log, which is stored in a hidden, dedicated arbitration mailbox that can only be accessed by using the EAC, the Search-AdminAuditLog cmdlet, or the New-AdminAuditLogSearch cmdlet. The following sections provide information about:
What's included in the admin audit log.
Reports available on the EAC Auditing page.
Admin audit log search cmdlets.
Audit log contents
Each audit log entry contains the information described in the following table. The audit log contains one or more audit log entries. The number of audit log entries is controlled by the audit log age limit specified using the
Set-AdminAuditLogConfig -AdminAuditLogAgeLimit command. Any audit log entry that exceeds the age limit is deleted.
Audit log entry fields
||This field is used internally by Exchange.
||This field contains the object that was modified by the cmdlet specified in the
||This field contains the name of the cmdlet that was run by the user in the
||This field contains the parameters that were specified when the cmdlet in the
||This field contains the properties that were modified on the object in the
Important: This field is only populated if the LogLevel parameter on the Set-AdminAuditLogConfig cmdlet is set to
||This field contains the user account of the user who ran the cmdlet in the
||This field specifies whether the cmdlet in the
||This field contains the error message generated if the cmdlet in the
||This field contains the date and time when the cmdlet in the
||This field indicates the server on which the cmdlet specified in the
||This field is used internally by Exchange.
||This field is used internally by Exchange.
||This field is used internally by Exchange.
EAC auditing reports
The Auditing page in the EAC has several reports that provide information about various types of compliance and administrative configuration changes. The following reports provide information about configuration changes in your organization:
Administrator role group report: This report enables you to search for changes to management role groups that you specify within a specified timeframe. The results that are returned include the role groups that have been changed, who changed them and when, and what changes were made. A maximum of 3,000 entries can be returned. If your search might return more than 3,000 entries, use the Administrator audit log report or the Search-AdminAuditLog cmdlet.
Admin audit log report: This report enables you to view entries in the admin audit log recorded within a specified time frame. You can also export admin audit log entries to a XML file and then send the file via email to a recipient you specify. For more information about the contents of the XML file, see Administrator audit log structure.
For information about how to use these reports, see Search the Administrator Audit Log.
When you run the Search-AdminAuditLog cmdlet, all the audit log entries that match your search criteria are returned. You can specify the following search criteria:
Cmdlets: Specifies the cmdlets you want to search for in the admin audit log.
Parameters: Specifies the parameters, separated by commas, you want to search for in the admin audit log. You can only search for parameters if you specify a cmdlet to search for.
End date: Scopes the admin audit log results to log entries that occurred on or before the specified date.
Start date: Scopes the admin audit log results to log entries that occurred on or after the specified date.
Object IDs: Specifies that only admin audit log entries that contain the specified changed objects should be returned
User IDs: Specifies that only the admin audit log entries that contain the specified IDs of the user who ran the cmdlet should be returned.
Successful completion: Specifies whether only admin audit log entries that indicated a success or failure should be returned.
Each audit log entry contains the information described in the table in Audit log contents. By default, only the first 1,000 log entries that match the search criteria are returned. However, you can override this default and return more or fewer entries using the ResultSize parameter. You can specify a value of
Unlimited with the ResultSize parameter to return all log entries that match the specified criteria.
For information about how to use the Search-AdminAuditLog cmdlet, see Search the Administrator Audit Log.
The New-AdminAuditLogSearch cmdlet searches the admin audit log just like the Search-AdminAuditLog cmdlet. However, instead of displaying the results of the search in the Exchange Management Shell, the New-AdminAuditLogSearch cmdlet performs the search and then sends the results to a recipient you specify via an email message. The results are included as an XML attachment to the email message.
You can use the same search criteria with the New-AdminAuditLogSearch cmdlet that's used on the Search-AdminAuditLog cmdlet. For a list of the search criteria, see Search-AdminAuditLog cmdlet.
After you run the New-AdminAuditLogSearch cmdlet, Exchange may take up to 15 minutes to deliver the report to the specified recipient. The XML file attached report can be a maximum of 10 MB. The XML file contains the same information described in the table in Audit log contents. For more information about the structure of the XML file, see Administrator audit log structure.
Outlook Web App doesn't allow you to open XML attachments by default. You can either configure Exchange to allow XML attachments to be viewed using Outlook Web App, or you can use another email client, such as Microsoft Outlook, to view the attachment. For information about how to configure Outlook Web App to allow you to view an XML attachment, see View or configure Outlook on the web virtual directories in Exchange Server.
For information about how to use the New-AdminAuditLogSearch cmdlet, see Search the Administrator Audit Log.
Manual admin audit log entries
In addition to logging Exchange cmdlets when they're run, Exchange Server enables you to manually write log entries to the audit log. Exchange Server supports this using the Write-AdminAuditLog cmdlet. Situations where you might want to add a manual log entry include the following:
Custom script entry and exit
Change control information
Maintenance start and end times
With the Write-AdminAuditLog cmdlet, you specify a string of text to include in the audit log using the Comment parameter. The Comment parameter accepts an alphanumeric string up to 500 characters. Included in the manual audit log entry along with the comment string is all of the same information captured when an Exchange cmdlet is logged. For a description of each field included in the audit log, see the table in Audit log contents.
You can retrieve manual audit log entries the same way as any other log entry, using the EAC Auditing page or using the Search-AdminAuditLog or New-AdminAuditLogSearch cmdlets.
To view the contents of the Comment parameter on the Write-AdminAuditLog cmdlet in a manual audit log entry, see Search the Administrator Audit Log.
Active Directory replication
Administrator audit logging relies on Active Directory replication to replicate the configuration settings you specify to the domain controllers in your organization. Depending on your replication settings, the changes you make may not be immediately applied to all servers running Exchange in your organization.
Admin Audit Log agent
The Admin Audit Log built-in cmdlet extension agent performs admin audit logging of cmdlet operations in Exchange Server. This agent reads the audit log configuration and then performs an evaluation of each cmdlet run in your organization. If the criteria you've specified in the admin audit log configuration matches the cmdlet that's being run, the agent generates an audit log entry.
The Admin Audit Log agent is enabled by default, which is required for admin audit logging to function. It can't be disabled, and its priority can't be changed. For more information about cmdlet extension agents, see Cmdlet Extension Agents.
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