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Y2KBDS

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MAPI Limitations in Exchange 2003 Service Pack 2

I have an Exchange 2003 Server running in clusters. I have many stores on the exchange server. I recently had some users that were unable to connect and found an error relating to MAPI limitations met at 32 connections. I failed over the cluster to clear out the connections and that fixed the issue for now. I was told by Microsoft that they were certain this is why people were being denied access.

My question is what is the recommended solution to keep this from reoccurring. We have users with mobile devices, BBs, and attaching to multiple shared calendars.

Is the limit per store or per server? If I set a MAPI limit of 32 does that only effect the store or the server as a whole?

We have probably hundreds of users so we are not the largest environment.
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Mestha
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You need to check your network drivers. They should be dated 2008. The MAPI 32 error is a classic sign of the Scalable Network Pack issue. That is addressed by an update from Microsoft and updated network drivers.

-M
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Y2KBDS

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Not sure if I follow that. I spoke with Microsoft and they said that I could increase that 32 limitation but that it could cause performance issues. I am trying to understand the MAPI issue better. Please re-read my orginal question.
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Mestha
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ASKER

Sorry I didn't mean to come across as you didn't know what you were talking about it just didn't seem clear to me what you were saying but I do understand this new post. I will check into this more tomorrow and let you know. Thanks for the help.
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ASKER

Okay so I checked the drives on the NICs and they are alll up to date. Questn: if I see that a user has reached the 32 MAPI connections does that:
1. Effect other users in that Store from connecting?
2. Effect users on that server but under a different store from connecting?
3. Only effect that user?

After failing over the servers to clear out the MAPI connections I saw one other user get this error in the Event Logs but no complaint from the user.
A user shouldn't get anywhere near the MAPI connection limit. If they are then that would tend to indicate a connection issue. If it is happening with only one user then you may have to look at their workstation or anything else connecting to the mailbox.

-M
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ASKER

I understand that a user shouldn't get to this many connections. I am trying to understand that if they did how that effects other users on the emial server besides maybe causing slowness. No one has been able to answer the questions above. Even Microsoft who told me this caused others to not connect cannot explain this to me. I feel like this is going no where.
If you have a call with Microsoft outstanding then ask for it to be escalated. The fact that someone is hitting that number is an indication that something is wrong somewhere. The only time the limit started to cause widespread problems was during the SNP issues in 2007/2008. Before that it was relatively rare.
I have heard of the issue appearing with mobile devices and if a user is on wireless and is roaming between WAPs.

As for its impact - I do not know. It is such a rare event outside of NIC issues I cannot recall the last time I saw it.

-M