Does anyone know what is the maximum number of concurrent TCP/IP connections on Windows XP SP3? I am trying to load test a machine and would like to know what is the max number of tcp connections that can be opened by an application (in my case, java application) towards that machine.
Note that often you may be limited by the number of outbound connections supported on the client machine rather than by the number of concurrent connections possible. See this Socket Bind Error for how to tune MAX_USER_PORT to enable more outbound connections from the machine running the tests.
I found some very useful information here:
http://smallvoid.com/article/winnt-tcpip-max-limit.html
Related
I have a windows server 2012R2 and some critical corporate-related Programs that I have to monitor the number of TCP connections from those Programs to a specific server. unfortunately monitoring software dos not provide us with this ability (+ I am a Linux user) and I need a PowerShell script that gives me the number of active connections from a single process (given by the name) to the specific server. if anyone can help me with this I will be glad and thankful to hear it.
I have a high load application which spins in IIS in Windows Server 2012. How to determine how many simultaneius tcp connections can windows handle and how to increase it? I already change TcpNumConnections and MaxUserPort to maximum allowed values, and TcpTimedWaitDelay to minimum. It helps to increase throughput of VM, but is it possible to configure something for better perfomance? Does it depend on SynAttackProtection or something else? And what should be tcp autotuninglevel for maximum performance?
I'm running a websocket server (command line program) off port 9000 on a Windows 2008 server. I can't seem to figure out why it will not accept more than about 600 concurrent connections. Testing on my local machine, I can create thousands of concurrent connections. But on the server, I get the following error after about 600:
No connection could be made because the target machine actively refused it
I have tried adjusting registry entries for the max port number, and turning off the firewall to no avail. I have also tried a different websocket server implementation. Is there some other setting I need to change?
edit: I tried this on a Linux server as well with the same problem.
I found the problem:
It seems to be my client side internet connection. By running the same tests on a different network from the client side, I can create thousands of connections.
Is there a limit to the number of HTTP ports in a machine. I have a windows application that uses .NET Remoting. Each instance of the application, exposes a Remote object on load, through a HTTP Channel with port 0 (so that port can be decided dynamically). In a Multi user environment, will there be a limit to the number of HTTP Ports.
Thanks in Advance!
Yes there will be a limit to the number of ports available which is 65535 minus the number of ports already in use for existing services (for example, SMTP [25], HTTPS [443], SQL Server [1433], etc).
So on a typical Windows server, a finger in the air calculation would be 65535 - 1024 (the well know service ports <= 1024 which are considered out of bounds) - another 10-20 or so possible other application (SQL Server, MySQL, Oracle, etc). This would leave around 64490 post available.
However will you really be running 64000 of instances of your server?
In .NET I have already tried the configuration below successfully:
<system.net>
<connectionManagement>
<add address="*" maxconnection="100"/>
</connectionManagement>
</system.net>
Using 100 concurrent HttpWebRequest they answered almost simultaneously (less than a second).
I wonder why some people wrote in some forums that Windows XP and Windows Server 2008 limits this number to 15 or 20. They are right?
The client versions of Windows are restricted in the number of half-open connections.
The 10 limit for XP is well known, Vista has other limits depending on the version (e.g. Home Basic has a limit of 2, Ultimate has 25).
You can Google "Patch for Event ID 4226" to alleviate these limits. Post Vista SP2 the behavior is configurable through a registry key.
Windows Server can handle several tens of thousands of concurrent inbound connections given enough resources.
Depending on your server version, you have to change some default parameters to allow these many connections to see this guide.
The author reports having seen 50.000+ concurrent connections to IIS6 on WS03SP1 x64 with 4GB RAM.
It could be because people are confusing the number of inbound SMB connections with the number of TCP/IP connections. SMB is used for file sharing and various other things and is limited to 10 connections in Windows Client OSes.
http://support.microsoft.com/kb/328459
There are connection limitations on uncompleted (new) connections. IIRC, this was rolled into a update a few years ago as an experiment to curtail the spread of certain types of malware. You can safely remove this limit:
http://technet.microsoft.com/en-us/magazine/2007.12.network.aspx