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