Probe port assignments / when to use first_probe_port

Discussion created by koert_struijk on May 3, 2011

Most probes are of the daemon type and will have a command port so that you can communicate with them.


The port to be used can be system assigned, or assigned by the controller.


Assignment by the controller is enabled by defining first_probe_port in the controller configuration - then the controller will assign consecutive port numbers to the probes as they are started.

Nimsoft has only reserved ports 48000 – 48003 (for controller, spooler, hub and tunnel). If you encounter other application using ports in your port range, you will need to change the first_probe_port.


When first_probe_port is not set, you will be using ports allocated by the system. These will be in a reserved range (ports in this range are reserved specifically for this type of use).

If you get a problem with another application, it will be the other applications' fault.


Making port assignment predictable is usually necessitated by firewall issues. It comes with a cost: you get into problems if one of the ports in the range you use is already taken. This is why I would recommend not using the first probe port option in unless you actually need it.


Here is information about reserved ports:



Usually system assigned ports will be in the in the "Dynamic, private or ephemeral ports" range where no applications can reserve ports.


Some windows specific information:

from http://msdn.microsoft.com/en-us/library/ms737550%28v=vs.85%29.aspx

"For TCP/IP, if the port is specified as zero, the service provider assigns a unique port to the application from the dynamic client port range. On Windows Vista and later, the dynamic client port range is a value between 49152 and 65535. This is a change from Windows Server 2003 and earlier where the dynamic client port range was a value between 1025 and 5000. The maximum value for the client dynamic port range can be changed by setting a value under the following registry key:


The MaxUserPort reistry value sets the value to use for the maximum value of the dynamic client port range. You must restart the computer for this setting to take effect.

On Windows Vista and later, the dynamic client port range can be viewed and changed using netsh commands. The dynamic client port range can be set differently for UDP and TCP and also for IPv4 and IPv6. For more information, see KB 929851. "


Regards, Koert