Verbindung von Outlook zu Exchange Server bricht scheinbar willkürlich ab

Hi

Ich hätte da ein paar Fragen.
Hast du dir mal den Switch angeschaut ? gibt es CRC Fehler oder sonstiges in den Logs des Switches ?
Wie viele PCs bzw. Benutzer hängen an dem Server ?
Gibt es mehr als 5 Benutzer die das selbe Postfach verwenden ? Auch Vollzugriff auf ein Postfach zählt als verwenden.

Was steht im Eventlog auf dem PC wenn das passiert ? keine fehler ?

LG Andy

Switch war auch mein erster Gedanke - aber wenn er die Truhe pingen kann (und ich hoffe nicht nur viermal), fällt das wohl flach ...

LG, Thomas

Nicht umbedingt. Ich hatte schon fälle die zwar eine verbindung hatten aber mit grösseren Packeten Probleme hatten.
Nachschauen im Log würde ich auf jeden fall.

Mal schaun was er so schreibt.

LG

Hi

Schau mal ob du über eine der Limits kommst :

Exchange Store Limits
http://technet.microsoft.com/en-us/library/ff477612(v=exchg.141).aspx


Exchange 2010
7 out of 16 rated this helpful - Rate this topic
Applies to: Exchange Server 2010 SP2
Topic Last Modified: 2012-03-08
In Microsoft Exchange Server 2010, connection and usage limits have been placed on the Exchange store to prevent a single application or a single user from using all the available connections to the Exchange store. If a single user or application is allowed to use all of the connections, other users or applications cannot be able to access the Exchange store, which could result in downtime.
Note:

For any connections made by accounts that have administrative privileges, the session limits have been increased to 64,000 maximum sessions per server.
Contents
Terminology
Session Limits
Open Item Limits
Item Size Limits
Terminology
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Knowledge of the following terms will help you understand the types of connections referenced in this topic.
Sessions
Sessions represent the connections used by services and client applications, such as Microsoft Outlook, to connect to the Exchange store. Services and clients can have multiple sessions at a particular time. The terms connections and sessions can be used interchangeably.
Threads
Threads represent concurrently executing requests to the Exchange store. For example, if a user opens a folder in Outlook, Outlook executes a request to the Exchange store on behalf of the user. That executing request is a single thread.
For example, 75 users being logged on to a server at the same time is equal to 75 sessions. However, out of those 75 sessions, only 5 of those sessions could be making requests through threads.
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Session Limits
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The following table lists the types of client connections to the Exchange store and the limits based on those connections. If you want to modify the session limits, see "Configure Session Limits" immediately following the table.
The types of connections are as follows:
• Max concurrent threads per server Specifies the maximum number of concurrent threads that an Exchange service can execute on a Mailbox server.
• Max sessions per server Specifies the maximum number of sessions that an Exchange service can have open at one time on a Mailbox server.
• Max user sessions per server Specifies the maximum number of sessions for a particular protocol for a single user.
Client type Max concurrent threads per server Max sessions per server Default number of user sessions per server
Admin 50 10,000 Not applicable
Availability service 50 10,000 16
Content indexing 50 10,000 Not applicable
Exchange ActiveSync Not applicable Not applicable 16
Exchange Web Services Not applicable Not applicable 16
Management Not applicable Not applicable 16
MAPI on the Middle Tier (MoMT) Not applicable Not applicable 32
MSExchangeMailboxAssistants: Events 50 10,000 Not applicable
MSExchangeMailboxAssistants: Timed 50 10,000 Not applicable
MSExchange Remote Procedure Call Not applicable Not applicable 16
Microsoft Office Outlook Web App Not applicable Not applicable 16
POP3 and IMAP4 Not applicable Not applicable 16
Transport 50 10,000 Not applicable
Unified Messaging Not applicable Not applicable 16
Others Not applicable Not applicable 16
Configure Session Limits
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You can modify the default session limits.
Note:

If you want to modify the session limits, you need to modify them on all Mailbox servers within any database availability groups (DAGs). If you don't make the same changes on all servers, the results will be inconsistent. To increase the session limit on the Client Access server, the RCAMaxConcurrency value must be increased on the throttling policy. For more information, see Set-ThrottlingPolicy.

Caution:

Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.
1. Start Registry Editor (regedit).
2. Navigate to the following registry subkey:
\\HKEY_LOCAL_MACHINE \SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem.
3. Right-click ParametersSystem, point to New, and then click DWORD (32-bit) Value.
The new value is created in the result pane.
4. Rename the key to one of the following values, and then press Enter:
o Maximum Allowed Sessions Per User This limit specifies the maximum allowable sessions per user.
o Maximum Allowed Service Sessions Per User This limit specifies the maximum allowed service sessions per user.
o Maximum Allowed Exchange Sessions Per Service This limit specifies the maximum allowed Exchange sessions per service. The default value is 10,000, and the Maximum value is 65536.
o Maximum Allowed Concurrent Exchange Sessions Per Service This limit specifies the maximum allowed concurrent Exchange sessions per service.
o Disable Session Limit This limit disables session limits. Set the value to 0 to turn off session limits. Set the value to 1 to turn on session limits.
5. Right-click the newly created key, and then click Modify.
6. In the Valuedata box, type the number of objects to which you want to limit this entry, and then click OK. Use the preceding table to view the default settings.
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Open Item Limits
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Open item limits are limits placed on the number of items that can be opened by a single mailbox in a single session. However, a user can have multiple sessions opened simultaneously. For example, if a user has two sessions opened, the user could open 1,000 folders.
If you want to modify these limits, see "Configure Open Item Limits" immediately following the table.
Item type Registry object type Max opened per session
ACL View objtACLView 50
Attachment objtAttachment 500
Attachment View objtAttachmentView 500
Cstream objtCStream 50
Folder objtFolder 500
Folder View objtFolderView 500
FX Destination Stream objtFXDstStrm 50
FX Source Stream objtFXSrcStrm 50
Message objtMessage 250
Message View objtMessageView 500
Notification objtNotify 500,000
Rule View objtRulesView 50
Stream objtStream 250
Configure Open Item Limits
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You can limit the maximum number of resources that a MAPI client can use simultaneously.
Note:

If you want to modify the open item limits, you need to modify them on all Mailbox servers within any DAGs and client access arrays. If you don't make the same changes on all servers, the results will be inconsistent.
Caution:

Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.
1. Start Registry Editor (regedit).
2. Navigate to the following registry subkey:
\\HKEY_LOCAL_MACHINE \SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
3. Right-click ParametersSystem, point to New, and then click Key.
A new key is created in the console tree.
4. Rename the key MaxObjsPerMapiSession, and then press Enter.
5. Right-click MaxObjsPerMapiSession, point to New, and then click DWORD (32-bit) Value.
The new value is created in the result pane.
6. Rename the key to <Object_type>, where <Object_type> is the name of the registry object type that you're modifying. For example, to modify the number of messages that can be opened, use objtMessage. Press Enter.
7. Right-click the newly created key, and then click Modify.
8. In the Value data box, type the number of objects that you want to limit this entry to, and then click OK. For example, type 350 to increase the value for the object.
9. Restart the Microsoft Exchange Information Store service.
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Item Size Limits
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Item size limits are the limits placed on items within a user's mailbox.
Item size limits are configurable by using the MaxSendSize and MaxReceiveSize parameters on the following cmdlets:
• Set-Mailbox
• Set-RemoteMailbox
• Set-MailUser
• Set-MailContact
Item type Limit
Message (saved) Maximum size of the SendLimit, ReceiveLimit
Message (sent) Maximum size of the SendLimit
Attachments Maximum number of attachments per message = 1,024
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LG Andy