Increasing MAPI Concurency connections per user in Exchange 2010

Customer is using MAPI account for helpdesk to handle support requests purpose. They want to configure same MAPI account in multiple machines. He is able to configure it in 9 machines but when they go to configure 10th machine it does not work. at any point of time  It is supporting only 9 machines, when we deleting one account which I have configured earlier, later if we try to configure in new machine it is configuring.

How it got resolved -

“Client throttling” feature is introduced in Exchange 2010 to ensure that a user should not use exchange server high resource. 

Among other things, client throttling helps you make sure that:

•              Users aren't intentionally taxing the system.

•              Users aren't unintentionally taxing the system.

•              Users of various connectivity methods are sharing resources proportionally.

Exchange 2010 has client throttling polices, which are enabled by default. You are probably exceeding your max connections configured value. For details,

Direct from Microsoft - http://technet.microsoft.com/en-us/library/dd298094.aspx

                                          http://technet.microsoft.com/en-us/library/dd297964.aspx

"The RCAMaxConcurrency parameter indicates how many concurrent connections an RPC Client Access user can have against a server running Exchange 2010 at one time. A connection is held from the moment a request is received until the connection is closed or the connection is otherwise disconnected (for example, if the user goes offline). If users attempt to make more concurrent requests than their policy allows, the new connection attempt fails. However, the existing connections remain valid. The RCAMaxConcurrency parameter has a valid range from 0 through 2147483647 inclusive. The default value is 20. To indicate that the number of concurrent connections should be unthrottled (no limit), this value should be set to $null"

Generally we  try to increase the CPUStartPercentage  when encounter these kind of issues, The CPUStartPercent parameter only applies to CPU usage and not concurrent connection parameters. For example, you set CPUStartPercent to 75% and RCAPercentTimeInCAS to 50%, if the CPU hits 75% utilization, Exchange will limit the amount of time Outlook can spend executing Client Access requests to 30 seconds out of every minute. No matter what the CPUStartPercent is set to, all parameters ralated to max concurrent connections will always be enforced.

Each client can have multiple RCA connections to the server if it is opening additional mailboxes, public folders, or shared folders. It is especially a problem if you are using Outlook 2003 as it doesn't release RCA connections that have been generated by viewing another user's calendar. Where you have so many clients connecting to the same mailbox, I would suggest you increase the RCAConcurrency to a higher value. You will need to monitor the Exchange server to ensure this doesn't cause any performance issues

To higher the value of  RCA connection do follow below steps:

·         Open EMS >>Get-ThrottlingPolicy |fl IsDefault,RCA*

·         Copy the  default throttlingpolicy and use in below command.

·         Open EMS>>Set-ThrottlingPolicy -Identity DefaultThrottlingPolicy_XXXXXXXXXXX -RCAMaxConcurrency 30

·         After run the command  just restart   “ RPC Client access service”.

Sometimes higher  the value in Client access server will not solve your concern since cut of connection limit has been set less in  Mailbox Server.  At those scenarios do follow the below steps.

·         On your mailbox server >> open “Regedit”  >>  go to the following key - \\HKEY_LOCAL_MACHINE \SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem

·         Create a new DWORD (32-bit) value called "Maximum Allowed Sessions Per User". Set this value to 100.

·         You may need to restart the information store for the change to take effect.

Your valuable feedback on this article is most appreciated

Regards, Raju

This posting is provided "as is" with no warranties and confers no rights.

Exchange 2010 - IMAP4/POP3 Read receipt Issue !!!

Issue:  Senders receiving read recipient notification report though email not read by a recipient. And few other cases, it is observed MAPI users  are getting their email status read automatically in their outlook though they actually dint,  but these users are also Black berry POP users and  when they disabled their Blackberry POP account it works fine

How it got resolved –

This is the scenario with Microsoft Exchange server 2010.

The “SuppressReadReceipt” parameter specifies whether to stop duplicate read receipts from being sent to IMAP4/POP3 senders that are using the “Send read receipts for messages I send “option in their IMAP4/POP3 e-mail program.

By default, this option is set to $false. By default, IMAP4/POP3 senders that use the” Send read receipts for messages I send” option receive a read receipt in both of the following circumstances:

·         When messages they send are downloaded by the recipient.

·         When the recipient opens the message.

For All users in your organization:

ü  Open  EMS >> run the following command>> Set-PopSettings  -SuppressReadReceipt  $true

ü  Open  EMS >> run the following command>> Set-ImapSettings  -SuppressReadReceipt  $true

For on single user:

ü  Open EMS >> run the following command>>set-CasMailbox – identity  username  - pop SuppressReadReceipt  $true

ü  Open EMS >> run the following command>>set-CasMailbox – identity  username  -Imap SuppressReadReceipt  $true

After run the commands restart the following services on the server.

ü  MSExchange Transport service.

ü  MSExchange System Attendant Service.

ü  MSExchange  POP Service.

ü  MSExchange  IMAP Service.

The valid values and descriptions for this parameter are:

ü  $false   IMAP4 /POP3 users are sent a read receipt each time a recipient downloads a message. IMAP4 users are also sent a read receipt when the user opens the message.

ü  $true   IMAP4 /POP3 users that use the Send read receipts for messages I send option in their e-mail client programs only receive a read receipt when the recipient opens the message.

Your valuable feedback on this article is most appreciated

Regards, Raju

This posting is provided "as is" with no warranties and confers no rights.

My First Post - With lot of Excitement !!!

Hi All,

In fact, few days ago, I thought to start a blog or personal website on MS Exchange, but due to busy with my professional career I could not do that and almost forgot it.

I would like to thank one of my friends and well wishers Mr Harsha who was motivated and supported towards starting this blog.

From now onwards I would post and share my knowledge and experience as well real-time issues and resolutions on “MS Exchange Enterprise/hosting”.

You can also post me queries/issues, MS Exchange related, I would try to do my best to help you out.

Looking forward for your support, help and wishes to make my blog success.

Thanks in advance,

Regards, Raju