Emsa Port Blocker is a TCP blocking utility. What it does, is blocking unwanted tcp access from/to your computer. It is not a firewall, but up to some extent it could be regarded as a similar tool. Its purpose is to prohibit TCP access on certain ports and ip addresses. IT can also be used as a TCP monitor because it shows TCP connections currently active on the machine.
This program works two ways. It can be configured to block access to certain local ports, but it can also prohibit access to specified remote ports as well. For example, you may try adding the port '80' to remote blocked ports. You'll immediately notice that you have disabled your browser's capability from accessing the www. You can use this program to block unauthorized access to certain ports on your computer, for example network ports like TCP 135 or 139 and so on. You can also use the configuration to permit connections between local IP's, or block even those as desired. The program comes with a function allowing to detect local ip's and adding them to the 'allowed' IP list.