eG Monitoring
 

Measures reported by XChg13ImapTest

When you install Microsoft Exchange Server 2013, IMAP4 client connectivity is not enabled. To enable IMAP4 client connectivity, you need to start two IMAP services, the Microsoft Exchange IMAP4 service and the Microsoft Exchange IMAP4 Backend service. When you enable IMAP4, Exchange 2013 accepts unsecured IMAP4 client communications on port 143 and over port 993 using Secure Sockets Layer (SSL).

The Microsoft Exchange IMAP4 service runs on Exchange 2013 computers that are running the Client Access server role. The Microsoft Exchange IMAP4 Backend service runs on the Exchange 2013 computer that's running the Mailbox server role. In environments where the Client Access and Mailbox roles are running on the same computer, you manage both services on the same computer.

If clients connecting to the Exchange 2013 via IMAP4 complain of slowness in the connections or frequent rejection of connections, administrators may want to figure out where the bottleneck is - is it because of a command processing bottleneck on the server? is it because of slow RPC or LDAP calls to the server? or is it due to a improper server configuration? The XChg13ImapTest test provides accurate answers for these questions!

This test tracks SSL connections over IMAP4 and periodically reports the count of active, failed, and rejected connections. This way, the test alerts administrators to unusual spikes in rejections and failures. In addition, the test also measures the time taken by the server to process commands and to service LDAP and RPC calls to the IMAP4 service, thus accurately pinpointing the probable reasons for a high degree of latency in the IMAP4 connections.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Act_ssl_conn Indicates the the number of SSL or TLS connections that are currently open on the IMAP4 service. Number This is a good indicator of the current SSL connection load on the service.
Avg_process_time Indicates the average time taken to process commands. Secs A consistent increase in the value of this measure is a cause for concern, as it indicates a command processing bottleneck.

In the event of a slowdown in request processing by the IMAP4 service, you may want to compare the value of this measure with that of the Avg_ldap_lat and Avg_rpc_lat measures to determine what is exactly causing the processing delay.
Avg_ldap_lat Indicates the average time taken by an LDAP call to return results from the Mailbox server. Secs A consistent increase in the value of this measure is a cause for concern, as it indicates a slowdown when processing LDAP calls.

In the event of a slowdown in request processing by the IMAP4 service, you may want to compare the value of this measure with that of the Avg_process_time and Avg_rpc_lat measures to determine what is exactly causing the processing delay.
Avg_rpc_lat Indicates the average time it takes for a remote procedure call to return results from a Mailbox server. Secs A consistent increase in the value of this measure is a cause for concern, as it indicates a slowdown when processing RPC requests.

In the event of a slowdown in request processing by the IMAP4 service, you may want to compare the value of this measure with that of the Avg_ldap_lat and Avg_process_time measures to determine what is exactly causing the processing delay.
Current_conn Indicates the total number of connections that are currently open on the IMAP4 service. Number This is a good indicator of the current connection load on the IMAP4 service.
Connection_rate Indicates the rate at which clients connect to the IMAP4 service. Connections/Sec  
Connection_fail Indicates the number of connections that have failed since the last measurement period. Number Ideally, the value of this measure should be 0. In case of a non-zero value, use the detailed diagnosis of this measure to know what listen errors occurred. Typically, event IDs 1026 and 1037 are classified as listen errors.
Indication_errors Indicates the number of indication errors that occurred during the last measurement period. Number Ideally, this value should be 0.
Connection_reject Indicates the number of connections that have been rejected since the last measurement period. Number Ideally, the value of this measure should be 0. A high value of this measure could indicate that many IMAP4 connections are being rejected by the server. One of the common reasons for this is a very low IMAP4 connection limit setting on the server. If the number of connections exceeds this limit, then subsequent connections will be rejected by the server.

You may want to increase the Maximum IMAP4 connections that the server will accept at any point in time, so that no connections are rejected.

Curr_unauth_conn Indicates the number of current connections that are not authenticated. Number  
Login_fail Indicates the number of LOGIN commands that have failed since the last measurement period. Number Ideally, the value of this measure should be 0.
Logout_fail Indicates the number of LOGOUT commands that have failed since the last measurement period. Number Ideally, the value of this measure should be 0.
Login_rate Indicates the number of LOGIN commands per second. Number  
Logout_rate Indicates the number of LOGOUT commands per second. Number  
Login_tot Indicates the total number of LOGIN commands that have been received since the last measurement period. Number  
Ssl_conn Indicates the total number of SSL connections to the IMAP4 service since the last measurement period. Number This is a good indicator of the total SSL connection load on the IMAP4 service.
Proxy_curr_conn Indicates the current number of proxy connections open on the IMAP4 service. Number  
Proxy_conn_fail Indicates the number of proxy connections to the IMAP4 service that failed since the last measurement. Number