Checking Open Ports with Shields Up
Ok so say you open a port for a vendor and they claim it isn't open or you just want to test if you did it right. Or say you want to see if you have a port open on your home network and you don't feel like installing nmap. Easy way to test that.
-Open web browser (must be done on client network or server).
-Go to https://www.grc.com/x/ne.dll?bh0bkyd2
-Enter the port you want to check in the text box as shown and then click
-Now if the result is failed and it shows the port as open as shown below, you have successfully determined that the port is open. The reason for the failure is because shields up exists to help you make sure no ports are open which is the opposite of what we are trying to do here :).
-Another function that is handy is to click the button. This will let you know what common ports are open on the customer network. Handy if you're trying to lock stuff down (this only checks the first 1054 ports. You should use something like nmap if you would like to check all of them).