An Event ID 2009 "Number of sessions exceeds 2048" may be recorded in the
event log and/or clients may be unable to create new connections to the
This behavior can occur because computers that run Microsoft Windows NT clients and use excessive numbers of ports (more than 3,976 simultaneously) may run out of ports before TCP/IP releases closed connections. The TCP/IP-state computer dictates that when a connection is
closed, the connection is not released until two maximum segment lives
(MSLs) have passed. This state is defined as the Time-wait state. Since one MSL is defined as 120 seconds, it takes four minutes for a closed
connection to be released in TCP/IP.
: For more information on MSL and Time-wait, please refer to Internet RFC 793.
To resolve this behavior, you must make the following registry change:
: If you use Registry Editor incorrectly, you may cause serious problems that may
require you to reinstall your operating system. Microsoft cannot guarantee that you can solve
problems that result from using Registry Editor incorrectly. Use Registry Editor at your own
The registry value is:
Value Type: REG_DWORD - Time in seconds
Valid Range: 30-300 (decimal)
Default: 0xF0 (240 decimal)
Microsoft has confirmed this to be a problem in Microsoft Windows NT
Workstation version 3.51 and Microsoft Windows NT Server version 3.51. This
problem was corrected in the latest U.S. Service Pack for Windows NT
Workstation or Server version 3.51. For information on obtaining this
update, query "servpack" (without the quotation marks) in the Microsoft Knowledge Base.
For additional information about configuration options for Windows NT 4.0, click the article number below
to view the article in the Microsoft Knowledge Base:
How to Modify TCP/IP Maximum Retransmission Timeout
This registry entry was first added in Windows NT 3.51 Service Pack 5. Customers using Windows NT 3.51 need to apply Service Pack 5 before making this modification.