# Exchange Server Monitoring

**Exchange Server Versions Supported**: Exchange Server SE, Exchange 2019, Exchange 2016, Exchange 2013, Exchange 2010, Exchange 2007, Exchange 2003 and older versions.

**Prerequisites for monitoring Exchange Server:** Monitoring of Exchange Server is possible only if Applications Manager is running in a Windows System. Refer to the [Prerequisites Section](https://www.manageengine.com/products/applications_manager/help/prerequisites-for-applications-manager.html#ExchangeServer).

**Using the REST API to add a new Exchange server monitor:** [Click here](https://www.manageengine.com/products/applications_manager/help/restapi-mail-servers.html#exchange)

**Attributes Monitored:** Refer to [Exchange Server Parameters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#parameter) to know more about the attributes monitored.

To create an Exchange Server Monitor, follow the given steps:

1. Click on **New Monitor**. Choose **Exchange Server** under **Mail Servers**.
2. Enter a **Display name** for the new monitor that you're going to add.
3. Enter the IP address or hostname of the host in which the Exchange Server is running.
4. Select **Exchange Server Version**: *Exchange Server SE, Exchange 2019, Exchange 2016, Exchange 2013, Exchange 2010, Exchange 2007, Exchange 2003 or below.*
5. Select the **Server Role** to be monitored.
6. Choose the **Exchange Server Services** you want to monitor from the list.
7. Select the Exchange Server **Services** you want to monitor.
8. Provide the authentication details such as User Name, Domain Name, and Password for the system in which Exchange Server is running.
9. You can enter your own credential details or select preconfigured credentials details in Credentials Manager. If you wish to enter your own credentials, specify **username** and **password** details for the monitor.
10. Choose the **Mode of Monitoring**: *Powershell* or *WMI*. By default, the connectionURI will be detected. If necessary, it can be customized.
    [Know more about using the Powershell option](https://www.manageengine.com/products/applications_manager/help/enabling-powershell.html)
11. Enable the **Use CredSSP Authentication** option only if you want to fetch Exchange Queues metrics for non-mailbox roles in versions 2010 and above where the Applications Manager and Exchange server are in different domains. [Know more about using CredSSP authentication](https://www.manageengine.com/products/applications_manager/help/enabling-credssp-authentication.html)
12. Specify the **timeout** value in seconds. Value should be greater than *120* seconds. However, this is applicable only in **Powershell** mode of monitoring.
13. Enter the **polling interval** time in minutes.
14. If you are adding a new monitor from an Admin Server, [select a Managed Server](https://www.manageengine.com/products/applications_manager/help/enterprise-managed-server.html#managed-server).
15. Choose the **Monitor Group** from the combo box to which you want to associate the Monitor (optional). You can choose multiple groups to associate your monitor.
16. Click **Add Monitor(s)**. This discovers the Monitor from the network and starts monitoring them.

[Know more about Exchange Server's component-specific performance counters that Applications Manager monitors.](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Performance)

**Note:** Monitoring of Exchange Server is possible only if Applications Manager is running on a Windows system. Exchange Monitoring now supports data collection in two ways:

1. **WMI**
   - For users who have not installed or do not require Powershell.
   - To choose this mode, select the WMI Mode of Monitoring in the new monitor page.
   - Mailbox and Database Statistics for Mailbox Server Role is not available for this setting.
2. **Powershell**
   - In the new monitor page, choose the Powershell Mode of Monitoring.
   - [To use Powershell for data collection, make sure the proper steps have been followed to enable Powershell remoting.](https://www.manageengine.com/products/applications_manager/help/enabling-powershell.html)
   - If the user has not modified any ports or the connectionURI, it need not be customized. The default value for connectionURI will be used in this case.
   - **Use CredSSP Authentication** needs to be enabled only for fetching Exchange Queues in non-mailbox roles in versions 2010 and above where the Applications Manager and Exchange server are in different domains. [Click here for the steps to enable CredSSP](https://www.manageengine.com/products/applications_manager/help/enabling-credssp-authentication.html)

Applications Manager allows you to efficiently monitor various versions of your Exchange Server, providing detailed reports on performance, availability, and the functioning of server roles. It centralizes the collection of Exchange component-specific performance counters, helping you detect issues, send alerts, and prevent potential service outages or configuration problems. Users can proactively manage Exchange Servers and identify issues before they become critical.

Applications Manager gathers data related to each of your Exchange Server Roles:

- **Mailbox Server Role** — Monitor your mailbox and public folder databases and diagnose issues pertaining to all related messaging data.
- **Client Access Server Role** — Monitor overall client access like ActiveSync, .NET, OWA, Web Services connections and hardware performance.
- **Unified Messaging Server Role** — Track integrated dial-in access performance and monitor e-mail, voicemail, fax, calendar information and contacts.
- **Hub Transport Server Role** — Monitor the mail flow, routing, and delivery within the Exchange organization and identify disk performance bottlenecks.
- **Edge Transport Server Role** — Monitor EdgeSync services, Active Directory Application Mode, SMTP connection authentication, transport queue databases and logs.

Applications Manager supports monitoring of counters relevant to the following server roles:

- **Exchange Server 2019/SE Server roles:**
  - [Mailbox Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Mailbox)
  - [Edge Transport Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Edge)
- **Exchange Server 2016 server roles:**
  - [Mailbox Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Mailbox) | [Mailbox and Database Statistics](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Database) (This includes Client Access Role Counters too because Mailbox Server in Exchange 2016 includes all of the server components from Exchange 2013 Mailbox and Client Access roles.)
  - [Edge Transport Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Edge)
- **Exchange Server 2013 Server roles:**
  - [Mailbox Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Mailbox) | [Mailbox and Database Statistics](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Database)
  - [Client Access Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Client)
  - [Edge Transport Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Edge)
- **Exchange Server 2010 and 2007 Server roles:**
  - [Mailbox Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Mailbox) | [Mailbox and Database Statistics](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Database)
  - [Client Access Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Client)
  - [Hub Transport Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Hub)
  - [Edge Transport Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Edge)
  - [Unified Messaging Server Role Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Unified)
- **Exchange Server 2003 and older versions**
  - [Performance Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Performance)
- **Common Counters (For all versions and roles)**
  - [Exchange Services and Active-Directory Access Domain Controllers](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Overview)
  - [Host Performance Counters](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Host)
  - [Queues](https://www.manageengine.com/products/applications_manager/help/exchange-server-monitoring.html#Queues)

## Exchange Server - Monitored Parameters

Go to the **Monitors Category View** by clicking the **Monitors** tab. Click on **Exchange Server** under the **Mail Servers** table. Displayed is the Exchange Server bulk configuration view distributed into three tabs:

- **Availability** tab gives the Availability history for the past 24 hours or 30 days.
- **Performance** tab gives the Health Status and events for the past 24 hours or 30 days.
- **List view** enables you to perform [bulk admin configurations](https://www.manageengine.com/products/applications_manager/help/bulk-config.html).

### Mailbox Role Counters

| Attribute name | Description | 2007 | 2010 | 2013 | 2016 | 2019/SE |
|---|---|---|---|---|---|---|
| **POP & IMAP Connections** |  |  |  |  |  |  |
| Current POP Connections | The total number of POP connections opened since the computer was last started. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Current IMAP Connections | The total number of POP connections opened since the computer was last started. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **SMTP Connections** |  |  |  |  |  |  |
| Inbound Connections | The total number of currently inbound connections. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Outbound Connections | The number of connections that were currently outbound. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Messages Sent/sec | The rate at which outbound messages are being sent. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Messages Received/sec | The rate at which inbound messages are being received. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Latency Requirements Counters** |  |  |  |  |  |  |
| Database PageFault Stalls/sec | The rate of page faults that can't be serviced because there are no pages available for allocation from the database cache. This counter should be 0 on production servers. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Database I/O Reads Average Latency | The average time, in ms, to read from the database file. The average value should be below 200 ms. Maximum values shouldn't be higher than 1,000 ms. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Database I/O Writes Average Latency | The average time, in ms, to write to the database file. This latency should be less than the MSExchange Database\\I/O Database Reads (Recovery) Average Latency when battery-backed write caching is utilized. | ✓ | ✓ | ✓ | ✓ | ✓ |
| I/O Log Reads/sec | The number of times data was read from a log file. Specific to log replay and database recovery operations. | ✓ | ✓ | ✓ | ✓ | ✓ |
| I/O Log Writes/sec | The number of times a log buffer was written to the active log file. Specific to log replay and database recovery operations. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Log Record Stalls/sec | The number of log records that can't be added to the log buffers per second because the log buffers are full. The average value should be below 10 per second. Maximum values shouldn't be higher than 100 per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Log Threads Waiting | The number of threads waiting to complete an update of the database by writing their data to the log. The average value should be less than 10 threads waiting. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Message Queuing Counters** |  |  |  |  |  |  |
| Mailbox Messages Queued For Submission | The current number of submitted messages not yet processed by the transport layer. The threshold value should be below 50 at all times. Shouldn't be sustained for more than 15 minutes. | ✓ | ✓ | ✗ | ✗ | ✗ |
| Public Messages Queued For Submission | The current number of submitted messages not yet processed by the transport layer. The threshold value should be less than 20 at all times. | ✓ | ✓ | ✗ | ✗ | ✗ |
| **Message Queue Counters** |  |  |  |  |  |  |
| Messages Currently Queued for Delivery | Total number of messages currently waiting in all Exchange transport queues for delivery at a given point in time. | ✗ | ✗ | ✓ | ✓ | ✓ |
| Messages Queued For Delivery/sec | Rate at which messages are being queued for delivery across all Exchange transport queues, measured per second. | ✗ | ✗ | ✓ | ✓ | ✓ |
| **Information Store RPC Processing Counters** |  |  |  |  |  |  |
| IS RPC Requests | The number of client requests currently being processed by the RPC Client Access service. | ✓ | ✓ | ✓ | ✓ | ✓ |
| IS RPC Averaged Latency | The latency averaged for the past 1,024 packets, in ms. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Cache Statistics** |  |  |  |  |  |  |
| Number Of Cache Active Connections | The number of active connections in all data connection pools created for a specific PowerPivot service application instance. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Number Of Cache Idle Connections | The number of idle connections in all data connection pools created for a specific PowerPivot service application instance. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Number Of Cache Connections | The number of connections to the server stored in the cache. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Cache Total Capacity | The size of the cached server connection pool. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **RPC Client Throttling & Client Activity Counters** |  |  |  |  |  |  |
| Client RPC Average Latency | RPC Average Latency is server RPC latency, in ms, averaged for the past 1,024 packets. The threshold value should be less than 50 ms on average for each client. | ✓ | ✓ | ✓ | ✓ | ✓ |
| RPC Client BackOff/sec | The rate that the server notifies the client to back-off. Higher values may indicate that the server may be incurring a higher load resulting in an increase in overall averaged RPC latencies, causing client throttling to occur. | ✓ | ✓ | ✗ | ✗ | ✗ |
| Client: RPCs Failed/sec | The client-reported rate of failed RPCs since the store was started. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Client: RPCs Failed | The client-reported number of failed RPCs since the store was started. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Search Index Counters** |  |  |  |  |  |  |
| % Processsor Time of indexing | The percentage of elapsed processor time that the Exchange Search Service is actively consuming across all CPUs at a given point in time. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Crawler Mailboxes Remaining | The number of mailboxes still remaining to be crawled by the Exchange Search indexer at the current point in time. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Content Indexing Counters** |  |  |  |  |  |  |
| Percentage Processor Time of indexing | The amount of processor time being consumed to update content indexing within the store process. Full crawls increase overall processing time, but should never exceed overall store CPU capacity. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Average Document Indexing Time | The average, in ms, of how long it takes to index documents. The threshold value should be less than 30 seconds at all time. | ✓ | ✓ | ✓ | ✗ | ✗ |
| Full Crawl Mode Status | This counter is used to determine if a full crawl is occurring for any specified database. Possible values are 1 for going through a full crawl and 0 for not going through a full crawl. | ✓ | ✓ | ✗ | ✗ | ✗ |
| Average Latency of RPCs used to Obtain Content | The average latency, in ms, of the most recent RPCs to the Information Store service. These RPCs are used to get content for the filter daemon for the specified database. | ✓ | ✓ | ✗ | ✗ | ✗ |
| Crawler Mailboxes Remaining | Any value of 1 or higher indicates the mailboxes in the database are being crawled; when the crawl is completed, the value is set to 0. | ✗ | ✗ | ✓ | ✓ | ✓ |
| **Client-Related Search Counters** |  |  |  |  |  |  |
| Slow Find Row Rate | The rate at which the slower FindRow needs to be used in the mailbox store. The threshold value should be no more than 10 for any specific mailbox store. Higher values indicate applications are crawling or searching mailboxes, which is affecting server performance. | ✓ | ✓ | ✗ | ✗ | ✗ |
| Search Task Rate | The number of search tasks created per second. The threshold value should be less than 10 at all times. | ✓ | ✓ | ✗ | ✗ | ✗ |
| Slow QP Threads | The number of query processor threads currently running queries that aren't optimized. The threshold value should be less than 10 at all times. | ✓ | ✓ | ✗ | ✗ | ✗ |
| Slow Search Threads | The number of search threads currently running queries that aren't optimized. The threshold value should be less than 10 at all times. | ✓ | ✓ | ✗ | ✗ | ✗ |
| **Database Counters** |  |  |  |  |  |  |
| Log Bytes Writes/sec | The rate of bytes written to the log. The threshold value should be less than 10,000,000 at all times. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Database Cache Percent Hit | The percentage of database file page requests fulfilled by the database cache without causing a file operation. If this percentage is too low, the database cache size may be too small. The threshold value should be over 90% for companies with majority online mode clients and over 99% for companies with majority cached mode clients. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Database Cache Size in MB | The amount of system memory, in megabytes, used by the database cache manager to hold commonly used information from database files to prevent file operations. Maximum value is RAM-2GB. Use this counter along with store private bytes to determine if there are store memory leaks. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Version Buckets Allocated | The total number of version buckets allocated. The threshold value should be less than 12,000. The maximum default version is 16,384. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Log Threads Waiting | The number of threads waiting for their data to be written to the log to complete an update of the database. If this number is too high, the log may be a bottleneck. The threshold value should be less than 10 on average. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Log Generation Check Point Depth | Represents the amount of work in the log file count that needs to be redone or undone to the database files if the process fails. The threshold value should be below 500 at all times for the Mailbox server role. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Database Instances I/O Reads Avg Latency | The average length of time, in ms, per database read operation. The threshold value should be 20 ms on average. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Database Instances I/O Writes Avg Latency | The average length of time, in ms, per database write operation. The threshold value should be 50 ms on average. Maximum values of up to 100 ms are acceptable if not accompanied by database page fault stalls. | ✓ | ✓ | ✓ | ✓ | ✓ |

**Note:** The metrics under the **Mailbox and Database Statistics Counters** tab marked with **\*** are only supported in Applications Manager **version 172900 and above**.

### Mailbox and Database Statistics Counters

| Attribute name | Description | 2007 | 2010 | 2013 | 2016 | 2019/SE |
|---|---|---|---|---|---|---|
| **Top Mailboxes** |  |  |  |  |  |  |
| Mailbox User Name | Username of the Exchange Mailbox User. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Warning Quota Utilization* | The percentage of mailbox storage used relative to the warning quota set for the user's mailbox, in %. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Prohibit Send Quota Utilization* | The percentage of mailbox storage used relative to the Prohibit Send Quota limit, in %. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Prohibit Send and Receive Quota Utilization* | The percentage of mailbox storage used relative to the Prohibit Send and Receive Quota limit, in %. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Total Mailbox Size | The total amount of storage space occupied by the user's mailbox, in MB. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Number of Items | Specifies the number of items in mailbox. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Warning Quota* | Storage limit set for a mailbox, in MB. A warning message will be received when the mailbox size exceeds the specified limit. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Prohibit Send Quota* | Storage limit set for a mailbox after which the user is prohibited from sending any new emails, in MB. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Prohibit Send and Receive Quota* | Storage limit set for a mailbox after which the user is prohibited from both sending and receiving emails, in MB. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Last Logon Time* | Time of last login by the mailbox user. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Use Database Quota Defaults* | Allows mailboxes to inherit storage quota settings from the database level. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Inactive Mailbox Users** |  |  |  |  |  |  |
| Mailbox User Name | Username of the Exchange Mailbox User. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Last Logon Time | Time of last login by the mailbox user. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Days since Last Login* | Number of days that have passed since the user last logged into their mailbox. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Database Statistics (2010, 2013, 2016, 2019 & SE)** |  |  |  |  |  |  |
| Master Type | Specifies if the Mailbox Database is part of a DAG/Server. | ✗ | ✓ | ✓ | ✓ | ✓ |
| DAG Name / Server | The Database Accessibility Group name. DAG allows you to replicate your database where mail is stored across any number of servers. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Database Name | Name of the mailbox database. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Mount Status | The mount status of the mailbox stores on the server. Mailboxes contained in unmounted mailbox stores cannot receive incoming messages. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Mailbox Count | The total number of mailboxes that reside in all mailbox stores and public folders. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Database Size (GB) | The size of the mailbox database. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Available New Mailbox Space (GB) | Unallocated storage capacity within the mailbox database available for incoming emails. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Last Full Backup | Detailed information about backups performed on storage groups on the connected server. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Circular Logging Enabled | Specifies whether circular logging is enabled. Circular Logging saves storage by preventing transaction logs from building up on the Server. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Days Since Last Full Backup | Indicates the number of days passed since the last full backup operation was performed. | ✗ | ✓ | ✓ | ✓ | ✓ |
| **Database Statistics (2007)** |  |  |  |  |  |  |
| Database Name | Name of the mailbox database. | ✓ | ✗ | ✗ | ✗ | ✗ |
| Mount Status | The mount status of the mailbox stores on the server. Mailboxes contained in unmounted mailbox stores cannot receive incoming messages. | ✓ | ✗ | ✗ | ✗ | ✗ |
| Mailbox Count | The total number of mailboxes that reside in all mailbox stores and public folders. | ✓ | ✗ | ✗ | ✗ | ✗ |
| Storage Group | The Exchange storage group name. A Storage Group is a grouping of one or more Mailbox Databases along with Log Files and a Checkpoint File. Not available for versions later than 2007. | ✓ | ✗ | ✗ | ✗ | ✗ |
| **Database Availability Groups** |  |  |  |  |  |  |
| Database Availability Group Name | The name of the database availability group. | ✗ | ✓ | ✓ | ✓ | ✓ |
| DAG Members | The database availability group members. | ✗ | ✓ | ✓ | ✓ | ✓ |
| DAG Members Count | The number of members in the particular database availability group. | ✗ | ✓ | ✓ | ✓ | ✓ |
| **Database Copy Statistics** |  |  |  |  |  |  |
| Database Name | The name of the mailbox database. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Database Status | The current status of the database. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Copy Queue Length | The number of transaction log files waiting to be copied to the passive copy log file folder. A copy is not considered complete until it has been checked for corruption. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Content Index State | The state of Microsoft Exchange Server content indexes. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Latest Full Backup Time | Last full backup time for the mailbox database. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Active Copy | If the database copy is active, "True" is shown; if passive, "False" is shown. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Days Since Latest Full Backup | Indicates the number of days passed since the latest full backup operation was performed. | ✗ | ✓ | ✓ | ✓ | ✓ |

Possible **Database Status** values include:

- *Failed* — The mailbox database copy is in a Failed state because it is not suspended and is unable to copy or replay log files.
- *Seeding* — The mailbox database copy or its content index is being seeded.
- *SeedingSource* — The mailbox database copy is used as a source for a database-copy seeding operation.
- *Suspended* — The mailbox database copy was manually suspended by an administrator.
- *Healthy* — The mailbox database copy is successfully copying and replaying log files.
- *ServiceDown* — The Microsoft Exchange Replication service is unavailable or not running on the server.
- *Initializing* — The system is verifying that the database and log stream are in a consistent state.
- *Resynchronizing* — The mailbox database copy and log files are being compared with the active copy for divergence.
- *Mounted* — The active copy is online and accepting client connections.
- *Dismounted* — The active copy is offline and not accepting client connections.
- *Mounting* — The active copy is coming online but not yet accepting client connections.
- *Dismounting* — The active copy is going offline and terminating client connections.
- *DisconnectedAndHealthy* — The mailbox database copy is no longer connected to the active copy and was Healthy when connectivity was lost.
- *DisconnectedAndResynchronizing* — The mailbox database copy is no longer connected to the active copy and was Resynchronizing when connectivity was lost.
- *FailedAndSuspended* — The system has set the Failed and Suspended states simultaneously, requiring administrator intervention.
- *SinglePageRestore* — A single page restore operation is occurring on the mailbox database copy.

For the Status attribute, the desired status is either Mounted for the server where the database is mounted, or Healthy for servers holding a copy. The ContentIndexState attribute should always be Healthy.

Possible **Content Index State** values include:

- *Crawling* — Database content is being indexed.
- *Disabled* — Indexing has been disabled by an administrator.
- *Failed* — An error has caused the content index to fail.
- *FailedAndSuspended* — Failed and Suspended states have been set simultaneously.
- *Healthy* — The Content Index is up to date and has not detected any issues.
- *Seeding* — A database copy is updating its Content Index from another database copy.
- *Suspended* — An administrator has manually paused or suspended updates from the active copy.

### Client Access Server Role Counters

| Attribute name | Description | 2007 | 2010 | 2013 | 2016 | 2019/SE |
|---|---|---|---|---|---|---|
| **ASP.NET Counters** |  |  |  |  |  |  |
| Application Restarts | The number of times the application has been restarted during the Web server's lifetime. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Worker Process Restarts | The number of times a worker process has restarted on the computer. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Request Wait Time | The number of ms the most recent request was waiting in the queue. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **ActiveSync Counters** |  |  |  |  |  |  |
| ActiveSync Requests/sec | The number of HTTP requests waiting to be assigned to a thread. Average of 50–100. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Pending Ping Commands | The number of ping commands currently pending on the server. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Pending Sync Commands | The number of sync commands currently pending on the server. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Requests Queued | The number of HTTP requests queued in a thread. | ✓ | ✓ | ✗ | ✗ | ✗ |
| **Availability Service Counters** |  |  |  |  |  |  |
| Availability Requests/sec | The number of requests in the application request queue per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Average Time to Process a Free Busy Request | The average time to process a free/busy request in seconds. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Current requests | The number of HTTP requests waiting to be assigned to a thread. | ✗ | ✗ | ✓ | ✓ | ✓ |
| Mailbox Session Hits/sec | The number of hits in a mailbox session. | ✓ | ✓ | ✗ | ✗ | ✗ |
| Public Folder Queries/sec | Number of mailboxes for which free/busy information is requested from public folders per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Public Folder Request Failures/sec | The number of public folder free/busy requests failed per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Outlook Web Access Counters** |  |  |  |  |  |  |
| Current Users | The number of users currently logged on to Outlook Web Access. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Outlook Requests/sec | The number of Outlook requests processed each second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Average Search Time | The average time elapsed while waiting for a search to complete. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Searches timed out | The number of Outlook requests timed out. | ✗ | ✗ | ✓ | ✓ | ✓ |
| OWA Average Response Time | Average time in milliseconds between the beginning and end of an OEH or ASPX request. The threshold should be less than 100 ms. | ✗ | ✗ | ✓ | ✓ | ✓ |
| **Autodiscover Counters** |  |  |  |  |  |  |
| Discover Requests/sec | The number of Autodiscover service requests processed each second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **WebService Counters** |  |  |  |  |  |  |
| Current Connections | The current number of connections established with the Web service. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Connection Attempts/sec | The rate at which connections to the Web service are attempted. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Current ISAPI Extension Requests | The rate at which Internet Server API extension requests are received by the Web service. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Other Request Methods/sec | The rate at which HTTP requests are made that do not use standard HTTP or WebDAV methods. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Requests/sec | The number of requests processed each second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Completed requests/sec | The number of requests completed each second. | ✗ | ✗ | ✓ | ✓ | ✓ |
| **RPC Client Access Counters** |  |  |  |  |  |  |
| Client RPC Average Latency | The average latency, in milliseconds, of RPC requests made to the Exchange Information Store over the last 1,024 packets. | ✓ | ✓ | ✓ | ✓ | ✓ |
| RPC Operations/sec | The rate at which RPC operations are processed by the Exchange Information Store per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| IS RPC Requests | The current number of RPC requests simultaneously active in the Exchange Information Store. | ✓ | ✓ | ✓ | ✓ | ✓ |
| User Count | The number of users currently connected to the Exchange RPC Client Access service. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Exchange Control Panel Counters** |  |  |  |  |  |  |
| Outbound Proxy Requests - Average Response Time | The average time, in ms, that requests sent to a secondary Client Access server took to complete. Threshold: under 6,000 ms. | ✗ | ✗ | ✓ | ✓ | ✓ |
| Requests - Average Response Time | The average time, in ms, the Exchange Control Panel took to respond. Threshold: under 6,000 ms. | ✗ | ✗ | ✓ | ✓ | ✓ |
| ASP.net Request Failures/sec | The number of failures per second detected by ASP.NET in the Exchange Control Panel. | ✗ | ✓ | ✗ | ✗ | ✗ |
| Powershell Runspaces - Average Active Time | The average time, in seconds, that a Windows PowerShell runspace stays active while executing cmdlets. | ✗ | ✓ | ✗ | ✗ | ✗ |
| Powershell Runspaces/sec | The number of Windows PowerShell runspaces created per second. | ✗ | ✓ | ✗ | ✗ | ✗ |
| RBAC sessions/sec | The number of RBAC sessions loaded per second. | ✗ | ✓ | ✗ | ✗ | ✗ |

### Hub/Edge Transport Role Counters

| Attribute name | Description | 2007 | 2010 | 2013 | 2016 | 2019/SE |
|---|---|---|---|---|---|---|
| **Transport Database Counters (HUB, EDGE)** |  |  |  |  |  |  |
| IO Log Writes/sec | The rate of log file write operations completed. | ✓ | ✓ | ✓ | ✓ | ✓ |
| IO Log Reads/sec | The rate of log file read operations completed. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Log Generation Checkpoint Depth | The amount of work, in log-file count, that needs to be redone or undone to the database files if the process fails. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Version Buckets Allocated | Total number of version buckets allocated. | ✓ | ✓ | ✓ | ✓ | ✓ |
| IO Database Reads/sec | The rate of database read operations completed. | ✓ | ✓ | ✓ | ✓ | ✓ |
| IO Database Writes/sec | The rate of database write operations completed. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Log Record Stalls/sec | The number of log records that cannot be added to log buffers per second because they are full. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Log Threads Waiting | The number of threads waiting for their data to be written to the log. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Transport Dumpster Counters (HUB, EDGE)** |  |  |  |  |  |  |
| Dumpster Size | The total size, in bytes, of mail items currently in the transport dumpster. | ✓ | ✓ | ✓ | ✗ | ✗ |
| Dumpster Inserts/sec | The rate at which items are inserted into the transport dumpster. | ✓ | ✓ | ✓ | ✗ | ✗ |
| Dumpster Item Count | The total number of mail items currently in the transport dumpster. | ✓ | ✓ | ✓ | ✗ | ✗ |
| Dumpster Deletes/sec | The rate at which items are deleted from the transport dumpster. | ✓ | ✓ | ✓ | ✗ | ✗ |
| **Transport Queue Length Counters (HUB, EDGE)** |  |  |  |  |  |  |
| Aggregate Delivery Queue Length All Queues | The number of messages queued for delivery in all queues. Threshold: less than 3,000 and not more than 5,000. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Active Remote Delivery Queue Length | The number of messages in the active remote delivery queues. Threshold: less than 250. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Active Mailbox Delivery Queue Length | The number of messages in the active mailbox queues. Threshold: less than 250. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Submission Queue Length | The number of messages in the submission queue. Threshold: less than 100. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Active Non-SMTP Delivery Queue Length | The number of messages in the drop directory used by a Foreign connector. Threshold: less than 250. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Retry Mailbox Delivery Queue Length | The number of messages in a retry state attempting to deliver to a remote mailbox. Threshold: less than 100. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Retry Non-SMTP Delivery Queue Length | The number of messages in a retry state in non-SMTP gateway delivery queues. Threshold: less than 100. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Retry Remote Delivery Queue Length | The number of messages in a retry state in remote delivery queues. Threshold: less than 100. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Unreachable Queue Length | The number of messages in the Unreachable queue. Threshold: less than 100. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Largest Delivery Queue Length | The number of messages in the largest delivery queues. Threshold: less than 200. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Poison Queue Length | The number of messages in the poison message queue. Threshold: 0. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Transport Load Assessment Counters (HUB, EDGE)** |  |  |  |  |  |  |
| Messages Submitted/sec | The number of messages queued in the Submission queue per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Messages Completed Delivery/sec | The number of messages delivered per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Inbound Local Delivery Calls/sec | The number of local delivery attempts per second. | ✓ | ✓ | ✓ | ✗ | ✗ |
| Average Bytes Per Message | The average number of message bytes per inbound message received. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Messages Received/sec | The number of messages received by the SMTP server each second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Messages Sent/sec | The number of messages sent by the SMTP send connector each second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Items Queued for Delivery/sec | The number of messages queued for delivery per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Inbound Message Delivery Attempts/sec | The number of attempts for delivering transport mail items per second. | ✓ | ✓ | ✓ | ✗ | ✗ |
| Messages Queued for Delivery/sec | The number of messages queued for delivery per second. | ✓ | ✓ | ✓ | ✓ | ✓ |

### Edge Transport Role Counters

| Attribute name | Description | 2007 | 2010 | 2013 | 2016 | 2019/SE |
|---|---|---|---|---|---|---|
| **Exchange-Agents** |  |  |  |  |  |  |
| Agent Name | The name of the agent counters. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Average Agent Processing Time in sec | The average agent processing time in seconds per event. Threshold: less than 20. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Total Agent Invocations | The total number of invocations since the last restart. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Message Hygiene Counters** |  |  |  |  |  |  |
| Average Scan Time | Average time taken to scan mailboxes as part of message hygiene using scheduled and on-demand scans. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Requests Rejected/sec | The number of scan requests in this application pool's queue that were rejected. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Requests Being Scanned | The number of scan processes currently running. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Requests Processing Time Per Request | The amount of time spent processing a request. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Antimalware Processing Time Per Request | The amount of time taken for the Antimalware engine to process an item. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Unhealthy Antimalware engines | Antimalware engines with errors in engine functioning. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Requests Fatal Errors | Percentage of submitted scan requests that encountered errors preventing their processing. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Request Timeouts | The number of scan requests that timed out in the last minute. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Processes Running | The number of scan processes currently running. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Time Per Request | The scan time per request. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Requests Processed/sec | The number of scan requests processed per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Request Wait Time Per Request | The time for which a scan request waits in the internal queue. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Requests Queued | The number of scan requests currently in the internal queue. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scan Requests Submitted/sec | The number of scan requests submitted per second, including accepted and rejected requests. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **SafetyNet Counters** |  |  |  |  |  |  |
| Resubmission Latency | Average time spent to resubmit each message when processing a Safety Net resubmit request. | ✗ | ✗ | ✗ | ✓ | ✓ |
| SafetyNet Resubmission Rate | The number of messages resubmitted from Safety Net. | ✗ | ✗ | ✗ | ✓ | ✓ |
| SafetyNet Resubmit Request rate | Number of resubmit requests made to Safety Net during the sampling period. | ✗ | ✗ | ✗ | ✓ | ✓ |
| Shadow SafetyNet Resubmission Rate | Total number of messages resubmitted from Shadow Safety Net. | ✗ | ✗ | ✗ | ✓ | ✓ |
| Shadow SafetyNet Resubmit Request rate | Number of shadow resubmit requests made to Shadow Safety Net during the sampling period. | ✗ | ✗ | ✗ | ✓ | ✓ |
| Resubmit Request rate | Total number of resubmit requests encountered per resubmit request state. | ✗ | ✗ | ✗ | ✓ | ✓ |

### Unified Messaging Server Role Counters

| Attribute name | Description | 2007 | 2010 |
|---|---|---|---|
| **Unified Messaging Counters** |  |  |  |
| Percentage of failed mailbox connection attempts over the last hour | The percentage of mailbox connection attempts that failed in the last hour. | ✗ | ✓ |
| Percentage of inbound calls rejected by the um service over the last hour | The percentage of inbound calls rejected by the Microsoft Exchange Unified Messaging service over the last hour. | ✗ | ✓ |
| Percentage of inbound calls rejected by the um worker process over the last hour | The percentage of inbound calls rejected by the UM worker process over the last hour. | ✗ | ✓ |
| Percentage of messages successfully processed over the last hour | The percentage of messages successfully processed by the Microsoft Exchange Unified Messaging service over the last hour. | ✗ | ✓ |
| Percentage of partner voice message transcription failures over the last hour | The percentage of voice messages for which transcription failed in the last hour. | ✗ | ✓ |
| Directory access failures | The number of times attempts to access Active Directory failed. | ✗ | ✓ |
| Calls disconnected on irrecoverable internal error | The number of calls disconnected after an internal system error occurred. | ✗ | ✓ |
| Operations over six seconds | The number of UM operations that took more than six seconds to complete. | ✓ | ✓ |
| Calls disconnected by callers during um audio hourglass | The number of calls during which the caller disconnected while Unified Messaging played audio hourglass tones. | ✓ | ✓ |
| Total inbound calls rejected by the um service | Total inbound calls rejected by the Microsoft Exchange Unified Messaging Service since service startup. | ✗ | ✓ |
| Total inbound calls rejected by the um worker process | Total inbound calls rejected by the UM Worker process since service startup. | ✗ | ✓ |
| Call answer queued messages | The number of messages created and not yet submitted for delivery. | ✓ | ✗ |
| Direct access failures | The number of times attempts to access Active Directory failed. | ✓ | ✗ |
| Hub transport access failures | The number of times attempts to access a Hub Transport server failed. | ✓ | ✗ |
| Unhandled exceptions/sec | The number of calls disconnected after an internal system error occurred in the last second. | ✓ | ✗ |
| Queued ocs user event notifications | The number of notifications created and not yet submitted for delivery. | ✓ | ✗ |
| Mailbox server access failures | The number of times the system did not access a Mailbox server. | ✓ | ✗ |

### Overview - Common Counters

| Attribute name | Description | 2007 | 2010 | 2013 | 2016 | 2019/SE |
|---|---|---|---|---|---|---|
| **Server Component States** |  |  |  |  |  |  |
| Component Name | Specifies the Exchange Component name. | ✗ | ✗ | ✓ | ✓ | ✓ |
| State | Specifies the Exchange Component Status. | ✗ | ✗ | ✓ | ✓ | ✓ |
| **Exchange Services** |  |  |  |  |  |  |
| Service Name | Specifies the Exchange Agent Service name. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Status | Specifies the Exchange Agent Service Status. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Availability | Specifies the availability of the Exchange Agent Service. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **AD Access Domain Controllers** |  |  |  |  |  |  |
| Domain Controller | The specified domain controller. | ✓ | ✓ | ✓ | ✓ | ✓ |
| LDAP Read Time | Time in milliseconds that an LDAP read request takes to be fulfilled. Average should be under 50 ms; maximum should not exceed 100 ms. | ✓ | ✓ | ✓ | ✓ | ✓ |
| LDAP Search Time | Time in milliseconds for an LDAP search request to be fulfilled. Threshold should be below 50 ms. | ✓ | ✓ | ✓ | ✓ | ✓ |
| LDAP searches timed-out per Minute | Number of LDAP searches that returned LDAP_Timeout during the last minute. Threshold should be below 10. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Long-running LDAP operations Per Minute | Number of LDAP operations on the domain controller that took longer than the threshold per minute. | ✓ | ✓ | ✓ | ✓ | ✓ |

### Host Performance Counters

| Attribute name | Description | 2007 | 2010 | 2013 | 2016 | 2019/SE |
|---|---|---|---|---|---|---|
| **Disk Utilization** |  |  |  |  |  |  |
| Free Disk Space | The percentage of free disk space. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Average Disk Reads/sec | Number of physical-disk reads per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Average Disk Writes/sec | Number of physical-disk writes per second. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Memory Utilization** |  |  |  |  |  |  |
| Memory Used | The memory space used by the server, in GB. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Free Physical Memory | The amount of free physical memory available, in %. | ✓ | ✓ | ✓ | ✓ | ✓ |
| % Memory Used | The percentage of memory space used by the server. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Total Memory | Total physical memory available to the operating system, in GB. | ✓ | ✓ | ✓ | ✓ | ✓ |
| **Exchange Domain Controllers Connectivity Counters** |  |  |  |  |  |  |
| Cache Hits/sec | Number of object-found-in-cache events per second. | ✓ | ✓ | ✓ | ✗ | ✗ |
| Cache Misses/sec | Number of objects-not-found-in-cache events per second. | ✓ | ✓ | ✓ | ✗ | ✗ |
| LDAP Searches/sec | Number of LDAP search requests issued by a process per second. | ✓ | ✓ | ✓ | ✗ | ✗ |
| Outstanding Asyncronous Reads | Number of outstanding LDAP read requests. | ✓ | ✓ | ✓ | ✗ | ✗ |
| **Memory Pages** |  |  |  |  |  |  |
| Pages Input/sec | Rate at which pages are read from disk to resolve hard page faults. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Pages Output/sec | Rate at which pages are written to disk to free physical memory. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Total Pages/sec | Rate at which pages are read from or written to disk to resolve hard page faults. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Page Reads/sec | Number of read operations, without regard to pages retrieved in each operation. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Page Writes/sec | Number of write operations, without regard to pages written in each operation. | ✓ | ✓ | ✓ | ✓ | ✓ |
| Transition Pages Repurposed/sec | Rate at which transition cache pages are reused for a different purpose. | ✓ | ✓ | ✓ | ✓ | ✓ |

**Note:** The metrics under the **Exchange Queues** section are mapped under **Settings → Performance Polling → Optimize Data Collection**.

### Queues

| Attribute name | Description | 2007 | 2010 | 2013 | 2016 | 2019/SE |
|---|---|---|---|---|---|---|
| **Exchange Queues** |  |  |  |  |  |  |
| Queue Name | The identity of the queue in the form of *<Server>\\ <Queue>*. [Learn more](https://docs.microsoft.com/en-us/exchange/mail-flow/queues/queues-and-messages-in-powershell?view=exchserver-2019#queue-identity) | ✗ | ✓ | ✓ | ✓ | ✓ |
| Status | The current queue status: *Active*, *Connecting*, *Suspended*, *Ready*, or *Retry*. [Learn more](https://docs.microsoft.com/en-us/exchange/mail-flow/queues/queues?view=exchserver-2019#queue-status) | ✗ | ✓ | ✓ | ✓ | ✓ |
| Message Count | The number of messages in the queue. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Velocity | The drain rate of the queue, calculated by subtracting Incoming Rate from Outgoing Rate. [Learn more](https://docs.microsoft.com/en-us/exchange/mail-flow/queues/queues?view=exchserver-2019#incomingrate-outgoingrate-and-velocity) | ✗ | ✓ | ✓ | ✓ | ✓ |
| Delivery Type | Indicates how the Transport service intends to transmit the message to the next hop. Possible values: *Internal*, *External*, *Undefined*. | ✗ | ✓ | ✓ | ✓ | ✓ |
| Next Hop Domain | The next domain where messages hop from the current queue. For delivery queues, this value is effectively the queue name. | ✗ | ✓ | ✓ | ✓ | ✓ |

### Exchange 2003 Performance Counters

| Attribute name | Description |
|---|---|
| **SMTP Connections** |  |
| Inbound Connections | The total number of connections that were currently inbound. |
| Outbound Connections | The number of connections that were currently outbound. |
| **SMTP statistics** |  |
| Local Retry Queue Length | The number of messages in the local retry queue. |
| Remote Retry Queue Length | The number of messages in the retry queue for remote delivery. |
| Remote Queue Length | The number of messages in the remote queue. |
| Messages Pending Routing | The number of messages that were categorized but not routed. |
| Messages in Local Delivery | The number of messages currently processed by a server event sink for local delivery. |
| Currently Undeliverable Messages | The number of messages reported as currently undeliverable by routing. |
| Categorizer Queue Length | The number of messages in the categorizer queue waiting to be categorized. |
| **POP & IMAP Connections** |  |
| Current POP Connections | The total number of POP connections opened since the computer was last started. |
| Current IMAP Connections | The total number of IMAP connections opened since the computer was last started. |
| **Information Store Mailbox statistics** |  |
| Receive Queue Size | The number of messages in the mailbox's receive queue. Threshold: below 500. |
| Send Queue Size | The number of messages in the mailbox's send queue. |
| Active Client Logons | Active client logons to Mailbox Stores during the specified time period. |
| Client Logons | Client logons to Mailbox stores during the specified time period. |
| Logon Operations Per Min | The number of logon operations to Mailbox stores per minute. |
| Message Recipients Delivered Per min | The message delivery rate. |
| Messages Delivered Per min | The message submission rate. |
| Messages Sent Per min | The message sent rate. |
| Mailbox Used Space | The amount of space used by the Mailbox. |
| **Information Store Public Folder statistics** |  |
| Send Queue Size | The number of messages in the public store's send queue. |
| Receive Queue Size | The number of messages in the public store's receive queue. |
| Active Client Logons | Active client logons to Public Folder Stores during the specified time period. |
| Client Logons | Client logons to Public Folder Stores during the specified time period. |
| Logon Operations Per Min | The number of logon operations to Public Folders per minute. |
| Messages Delivered Per min | The message delivery rate. |
| Message Recipients Delivered Per min | The message recipients delivery rate. |
| Messages Sent Per minute | The message sent rate. |
| Messages Submitted Per minute | The message submission rate. |
| Public Folders Used Space | The amount of space used by Public Folders. |
| **Information Store Connections & Users** |  |
| Information Store Active Connection Count | The number of connections that have shown activity in the last 10 minutes. |
| Information Store Connection Count | The number of client processes connected to the information store. |
| Information Store Active User Count | The number of user connections that have shown activity in the last 10 minutes. |
| **MTA statistics** |  |
| MTA Work Queue Length | The number of messages in the MTA work queue. |
| MTA Message Bytes Per Min | The rate at which message bytes are processed. |
| MTA TCP/IP Received Bytes Per Min | The rate at which bytes are received over a TCP/IP connection. |
| MTA TCP/IP Transmit Bytes Per Min | The rate at which bytes are transmitted over a TCP/IP connection. |
| MTA Total Recipients Queued | The maximum number of recipients permitted in the MTA queues. |
| MTA Work Queue Bytes | Total volume of messages, in MB, stored in the message transfer agent. |
| **Information Store statistics** |  |
| Current Pending Local Delivery | Messages currently pending in the MTA Queue. |
| Current message from MSExchangeMTA | Messages currently in transit from MSExchangeMTA to Exchange Store. |
| Currentmessages to MSExchangeMTA | Messages currently in transit to MSExchangeMTA from Exchange Store. |
| Messages Received Per Min | The number of messages received by the SMTP server each minute. |
| Messages Sent Per Min | The number of messages sent by the SMTP server each minute. |
| HSOT Cache Hits | The number of objects found in cache events per second. |
| **Directory & Event Service statistics** |  |
| Pending Replication Synchronizations | The number of directory synchronizations queued for this server. |
| Remaining Replication Updates | The number of directory synchronizations remaining. |
| Notify Queue | The queue of store notifications waiting to be processed. |
| Address Lists Queue Length | The number of entries in the Address List queue. |
| **Message Transfer Agent Connections** |  |
| MTA Queue Length | The number of outstanding messages queued for transfer. |
| MTA Queued Bytes | The total volume of message content, in MB, stored in the Message Transfer Agent queue. |
| MTA Current Inbound Associations | Number of inbound, remotely initiated, associations between the MTA and connected MTA. |
| MTA Current Outbound Associations | Number of outbound, locally initiated, associations between the MTA and connected MTA. |