Users exceeding the MAPI connection limit

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MarkieSA

Hi all,

I'm currently dealing with a problem on one of my Exchange 2003 servers, first I need supply some details, this Exchange server is clustered, has all the latest service packs and updates, there is approximately 2000 users on this server, it's running on Server 2003. Here is my problem, in one of our offices there is a few users that keep exceeding the MAPI connection limit which causes their Outlook client to hang, they will see a message every now and then saying that Outlook is trying to connect to the Exchange server and some times will eventually say " disconnected" . When I go into ESM I can see these users under " logons" and all of them have an exceptionally high amount of logons. This problem is only occuring in one location, no one else out of the 2000 users have reported this problem

What I've done as a test is move two of these users mailboxes to another Exchange server, they have currently been working without any problems for the last few hours, one problem I can see is that user A that was on Exchange server 4 is showing under " logons" on the server they were on, they now on Exchange server 5, under logons on server 5 they only have 4 or 5 logons, why are they showing up under " logons" on the server they were on, these are not old connections, the date and time stamp is after the user was moved to server 5. It's almost as if there is something on the clients machine that is trying to make additional MAPI connections.

I've tried running outlook in safe mode on a few machines, this works briefly then they start suffering the same problems again, once again the server will show event id 9646 saying that the user has exceeded the MAPI connection limit.
 
D

durkeep

I've seen this problem caused by a flakey connection, like maybe a bad ethernet card, or a bad cable at the client end, that causes that machine to constantly create new connections to the server. You can delete the old connections using TCPView from the sysinternals collection at http://live.sysinternals.com.
-Peter

-Peter
 
K

Khoj Sahiwala

Yes Durkeep is right .. You can delete the tcp connections , but be extremely careful when doing this.

I also had a similar problem and thsi happened becuase of TCP offloading feature and Wireless connection.

The soultions are delting the connections as mentioned by Durkeep.

Dismounting and mounting the DB whcih will reset all connections

moving the mailbox.. But if you can do a firmwarfe upgrade of the NIC card or the remote office where there is a wireless connection upgrading those to newer version woudl be a better soultion.

Regarding your query

I can see is that user A that was on Exchange server 4 is showing under " logons" on the server they were on, they now on Exchange server 5, under logons on server 5 they only have 4 or 5 logons, why are they showing up under " logons" on the server they were on, these are not old connections, the date and time stamp is after the user was moved to server 5. It's almost as if there is something on the clients machine that is trying to make additional MAPI connections

Old connections do stay for a while until resetted which is a bit dangerous as it kills the connections and may bring the Database in an inconsistent state if not used properly.
 
M

MarkieSA

Thanks for the replies guys. First of all I'm fully aware of TCPView, the problem with this is that this is a temporary fix killing the connections, I'm trying to find the root cause. The office which is having this problem connects to the Exchange server (which is half a continent away) over an MPLS link, where would be a good place to start looking at networking problems, I doubt very much the problem is on the Exchange server, as I said in my original post this server has over 2000 users on it of which no one is complaining other than this one office so the problem must be local to their office.

Khoj, the mailbox that I moved is creating new MAPI connections to the old server it used to be on, it's not stale connections from when it was on the server. The mailbox was moved from server A to server B, the users logon is still making new MAPI connections to the server it used to be on and the server it's currently on.
 
M

MarkieSA

Just as an FYI to everyone, we could not find the core reason to this problem. What we did is moved each mailbox to a different store on the same Exchange server which cleared out the MAPI logons for each individual user.

Now that the mailboxes have been moved we will monitor them to see if the users reach the logon limit again.
 
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