Hmmm. Not sure that the behavior you are experiencing is what I would expect in that case, but it certainly is possible.
Good luck! Regards, Michael B. Smith Consultant and Exchange MVP http://TheEssentialExchange.com From: Jim Holmgren [mailto:jholmg...@xlhealth.com] Sent: Monday, May 02, 2011 9:58 AM To: MS-Exchange Admin Issues Subject: RE: Too Many MAPI Connections Thanks Michael, A thought occurred to me as I was typing my question. That seems to happen a lot, I suspect it is the act of trying to organize thoughts to clearly convey the issue to others that causes it. Anyway, we have a pair of Expand network compression devices on either end of this link, and one of my other network guys implemented some throttling on "Exchange" connections as they were taking up too much of the 10Mbps pipe between us. This was done a couple of months ago, but there were no immediate issues reported. I am betting those would be MAPI connections, and I'm further wagering that they have added a significant number of new users in India. The pipe has been increased to 45Mbps, and the Expand devices are scheduled to be removed during a maintenance window on Friday night. I think I'm going to sit tight until those devices are removed and see if that fixes the issue. Jim From: Michael B. Smith [mailto:mich...@smithcons.com] Sent: Monday, May 02, 2011 9:50 AM To: MS-Exchange Admin Issues Subject: RE: Too Many MAPI Connections I spent a few minutes hunting for a reference on this (a Microsoft reference I mean) and I can't locate it but I've seen this with both F5 and Cisco load balancers before. Generally, you increase the NAT or TCP session lifetime on your firewall or LB, not the TCP Keepalive on the Exchange servers themselves. I'm not 100% sure that your NW Engineer understands what TCP Keepalive is. :) http://tldp.org/HOWTO/TCP-Keepalive-HOWTO/overview.html "Too many MAPI connections" instead generally means that a single account has too many active MAPI connections. This is generally because a prior connection (or multiple prior connections) were ignored and a new connection was created, or because of a program bug. NAT being torn down too quickly would lead directly to this issue. Regards, Michael B. Smith Consultant and Exchange MVP http://TheEssentialExchange.com From: Jim Holmgren [mailto:jholmg...@xlhealth.com] Sent: Monday, May 02, 2011 9:27 AM To: MS-Exchange Admin Issues Subject: Too Many MAPI Connections Good morning everyone, Our office in Bangalore connects via VPN tunnel back to our Exchange 2003 environment. Recently a number of users have been having difficulty connecting to their mailboxes (Outlook 2007 client). Upon investigation, we are seeing "too many MAPI connections" - so it appears that MAPI connections are not being closed correctly. We have checked for the presence of desktop search programs, having seen that cause similar issues in the past. We have disabled all of the desktop search engines, yet the issue continues. We have also recreated their MAPI profiles with no success. Our Exchange 2010 upgrade is entering UAT, so we are inching closer to migrating away from 2003, but I can't rush it. :) One of my network engineers is suggesting that we change the TCP KeepAlive timeout on the Exchange servers based on some research he has done online. Recommended value is 300,000 (5 minutes), and the default time for Exchange is 7,200,000 (2 hours). Looking for some thoughts - will changing this timeout cause any additional issues within Exchange? We could also increase the max number of MAPI connections, but I'm hesitant to do either change - I would rather find the root cause, but the issue is getting fairly hot and I need to get some relief even if only temporary. Jim Jim Holmgren Senior Manager, Infrastructure Services XLHealth Corporation The Warehouse at Camden Yards 351 West Camden Street, Suite 100 Baltimore, MD 21201 410.625.2200 (main) 443.524.8573 (direct) 443-506.2400 (cell) www.xlhealth.com<http://www.xlhealth.com> --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com<mailto:listmana...@lyris.sunbeltsoftware.com> with the body: unsubscribe exchangelist --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com<mailto:listmana...@lyris.sunbeltsoftware.com> with the body: unsubscribe exchangelist CONFIDENTIALITY NOTICE: This email, including attachments, is for the sole use of the intended recipient(s) and may contain confidential and/or protected health information. 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