Free f port software for windows

Server Port is a free widget that allows you to check whether or not a server is online, or if a determined port is open or not.
To use the Widget, enter the Widget Preferences and enter the information in the form of "server:port".

IP Port Spy is a tool that will listen on a TCP or UDP port, and print the frames received in the main window.
No frames are sent back in response to the frames received, although TCP connects are sent when a connect request is sent on a TCP port.
This software was developed with the IP developer in mind, as a means to test and debug network applications, or just to provide information about particular frames. The frames shown below in the main window are SNMP frames, with IP Port Spy listening on UDP port 161.

Flash Port Scanner is a fast and simple multithread port scanning tool. The program has a simple interface and its very easy to use.

AutoNOC Port Scan will rapidly analyze a PC to identify the available ports on a remote machine (and potentially vulnerable to break in).
AutoNOC Port Scan runs in parallel to instantly evaluate the services available on a remote device or node.

Not the best port scanner around but it works well and quite fast. It is useful for security audit of your personal computer.
Faltron Port Scanner scans for TCP listening/open ports on your or remote system. You can scan a range of ports or just a single port. You SHOULD NOT scan others system without their permission! I will not held responsible if you use it for illegal purposes.
The speed will be a bit slower when scanning remote system. You can double click on an open port to view more information on the DShield website.

Faltron Port Sniffer is a very simple data sniffer that will open a listening port for the local client to connect and direct the data to the server side and vice versa, in the process displaying the data to and from.
You must specify the local port for the client to connect to the sniffer and must not be already used by other process. You must also specify the remote IP or Host and the port for the client to connect to.
To check whether a local port is in use, go to the command prompt and type netstat -a (type netstat/? to know more about this command). You should use a port numbered 1024 and above. This is a experimental version, so there will be some bugs. I only tested and used in mIRC.

Will monitor ports on your computer that you specify to watch for threatening activity, including portscans. When such activity occurs, you are notified of the exact time when it happened, and the IP and hostname of who tried to compromise your system.