Beginner: Number of connections possible to server/mail server

Posted on 2003-02-26
Medium Priority
Last Modified: 2010-03-18

I am having problem with my network at work. When trying to send and recieve emails with Outlook 2000 I get the following error:

"TCP/IP connection was unexpectedly terminated by your mail server...."

According to a MS support webcast that error message indicates that too many connections has been made to the server.

The problem has been spontanous, sometimes I have no problem with the connection (get my email) and sometimes I don't. Regardless, my internet connetion has always been working, i.e. it is ONLY the email connections which is troublesome.

My question is now two-fold:

1. How many connections are there usually to a small business server with 4-5 users? Running netstat on the server indicates a huge amount of TCP connections open (active = 9000 and passive = 11000). I have no idea if this is normal or if the server is under too much stress.

2. Focusing on myself (my userid), I had one close_wait connection, could this mean I am only allowed this connection and I have to wait until it terminates until I get my mail access back?

Any help is appreciated!


Question by:PeterBergstrom
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Expert Comment

ID: 8028667
Sorry but are you connecting to a local mail server or your ISP's mail server

Accepted Solution

marsbar105 earned 200 total points
ID: 8028718
Hey Peter,

I checked out Microsoft bit on this and came up with this article for your issue.

Note in this article that you have to call microsoft to get the patch they created.  Usually they don't charge when they ask you to call.

good luck,


Author Comment

ID: 8031587
I am connecting to my local server but using POP3 to collect the mail. The server is collecting the mail from my ISP via ADSL.

I think I have solved the problem. It definitely seems like I have too few possible connections to my server/mail server, which results in a TCP-error when trying to establish a new connection (for example when I reboot the computer).

The annoying part with this is that I cannot do a fast reboot as it seems since my old connection will still hang around for a while. I have to shut down the computer and wait a minute or so...

What I need to do is to increase the number of possible connections (POP3?) to the mail server I guess...

Author Comment

ID: 8031625
...and Mars, I can't get that link to work :-( Neither can I find a document with number 811044 in the kb. Can you reach the article?


LVL 28

Expert Comment

ID: 8035185
His link worked for me.  Here's its contents.

Windows 2000 Stops Accepting Incoming TCP Connections
The information in this article applies to:
Microsoft Windows 2000 Advanced Server SP3
Microsoft Windows 2000 Advanced Server SP2
Microsoft Windows 2000 Advanced Server SP1
Microsoft Windows 2000 Server SP3
Microsoft Windows 2000 Server SP2
Microsoft Windows 2000 Server SP1
Microsoft Windows 2000 Professional SP3
Microsoft Windows 2000 Professional SP2
Microsoft Windows 2000 Professional SP1

A Windows 2000-based computer may stop accepting incoming TCP connections. If you run the netstat.exe -an command, you see that many connections are in the "CLOSING" state.
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows 2000 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

   Date         Time   Version        Size     File name
   13-Nov-2002  17:36  5.0.2195.6127  118,896  Afd.sys    
   09-Dec-2002  21:41  5.0.2195.6020  105,232  Msafd.dll  
   09-Dec-2002  21:41  5.0.2195.6155  313,616  Tcpip.sys  
   31-Jul-2001  01:15  5.0.2195.3988   16,240  Tdi.sys    
   09-Dec-2002  21:41  5.0.2195.4874   17,680  Wshtcpip.dll

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.
For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:
265173 The Datacenter Program and Windows 2000 Datacenter Server Product

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