Hi,

Setup: [Company Network <--> Windows Server 2003 acting as a NAT router <--> Private Network] We have a Windows Server machine setup as a NAT router to allow access to company file servers from the computers on a local (private) network
in a lab setup within the same building of the company. Because of the nature of the experiment/R&D setup, there is a need to have a local (private) network that can not directly access/connected to the rest of the company network.


Issue: If we have 2 computers on the private network running 140 processes each and each process is trying to access a different file on the same file server within the company, we get many "TCP/IP has reached the security limit imposed on the number of
concurrent TCP connect attempts" warnings in the event log and process terminates with "file could not be accessed" error, but if we run 280 processes from 1 computer on the private network to access 280 different files on the same company file server, everything
seems to run ok.

Help needed: Has anyone seen a similar issue before? Is there any suggestion on finding if there exists any limitation or setting in NAT router configuration that may avoid/solve the issue?

Additional Information: If we try to use 2 PC connected to company network for running 140 processes each and each process trying to access a different file on the same file server within the company, that also seems to be running ok. This hints that there
is some limitation/problem the way NAT router may be configured.

Thanks
Niresh

Need to support users over the internet? click here try our remote control online beta

Hi Niresh,

Thanks for posting here.

According to the testing you performed in this environment I think this is expected phenomenon and I believe this is some sort of self-protection mechanism at server level but no RRAS in order to make the server can healthy running and providing service
in best situation.

Event ID 4226 TCP/IP Network Performance

http://technet.microsoft.com/en-us/library/cc727819(WS.10).aspx


Some tips in the third party link below may will help us to adjust the settings :


http://smallvoid.com/article/winnt-tcpip-max-limit.html


Meanwhile, tips in the performance tuning guide for Windows server 2003 will also help us to optimize networking performance for this server in best practice :


http://download.microsoft.com/download/2/8/0/2800a518-7ac6-4aac-bd85-74d2c52e1ec6/tuning.doc


Important Note: This response contains a reference to a third party World Wide Web site. Microsoft is providing this information as a convenience to you. Microsoft does not control these sites and has not tested any software or information found on
these sites; therefore, Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. There are inherent dangers in the use of any software found on the Internet, and Microsoft cautions
you to make sure that you completely understand the risk before retrieving any software from the Internet.

Thanks.

Tiger LiTiger Li
TechNet Community Support

There is an amazing pack of free network admin tools. click here to download it