I have recently been suffering a spate of users being disconnected from Outlook.
We are running Exchange 2003 and the clients experiencing the problems are Outlook 2003 and 2007. All are on the same LAN.
In the Exchange server I got the following error message:
Event ID: 9646
Mapi session "/o=COMPANY NAME/ou=UK/cn=USERS/cn=JOHN.SMITH" exceeded the maximum of 32 objects of type "session".
IP connectivity was fine (they can browse shares on the mail server) and eventually (after an hour or so), they could connect back on to the Exchnage server.
I found this article http://support.microsoft.com/kb/842022 and made all the changes it recommended, increasing the limit from 32 to 64.
I've also got people to clear out their mailboxes so they don't have more than 3000 items.
but the disconnections still kept happening....
After contacting MS Support, I got the following suggestions:
On the Exchange servers:
1. HP network cards teaming enabled. This is a known cause for this type of scenario. If you have teaming enabled on the network cards, break it and retest without it.
2. TCP Chimney. Disable it by running the following command and rebooting afterwards: Netsh int ip set chimney DISABLED (http://support.microsoft.com/default.aspx?scid=kb;EN-US;242468)
3. Add the following registry key on the servers: MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\KeepAliveTime , DWORD, value 300000 ( that means 5 minutes in miliseconds)
We didn;t have network teaming enabled, so I just applied 2 and 3, and after a quick reboot, I had no more error messages.
I hope this hint helps you out, please feel free to click the ads on this page to show your thanks.