1

I need a software to monitor open ports on my network based on my internet IP address. I've used programs in here but they scan my LAN. I want to scan my WAN to see which ports are open and which aren't based on my internet IP, not my internal or router's.

Requirements:

  • must scan all ports (not just a subset)
  • must work "from the outside" (i.e. scan the WAN interface, not the local network)

It's useful when, for example, you want to check whether Bittorrent, Proxy etc. ports are currently blocked by ISP or not. thanks.

  • You would need to call that tool from the outside (e.G. a server you control). Do you have any infrastructure that you can use for this? If so, please specify the operating system of said device. – Angelo Fuchs Feb 9 '15 at 11:58
  • 1
    There are tons of WebApps that will to that for you, I just searched "scan open ports online" and found some. – Angelo Fuchs Feb 9 '15 at 12:01
  • i found them too but they either have some limitations or are not accurate and i just tried them and they show all ports success meaning open, but i still have some kind of problem with protocols. btw, why do i need to do this from outside? is it mandatory? shouldn't i try every port from inside of my network to find out which one is currently open or blocked? – user6306 Feb 9 '15 at 12:11
  • 1
    If you want to know if your ISP is doing the filtering you will need to send a signal through your ISP. Also, "having problems" can be caused by closed ports but does not have to be. If all your ports are open according to the tools, your problem is somewhere else :) It could be that a) you are not forwarding the ports to your machine b) your ISP performs Deep Packet Inspection and lets the TCP SYN through that the port scanners use, but not the actual content that you are expecting. (Or c: something I forgot) A complete analysis would be far beyond the scope of this question, though. – Angelo Fuchs Feb 9 '15 at 12:17
  • Apart from the fact that "have some limitations" doesn't correspond with the requirements you've listed (none except "to see which ports are open"). So it's pretty unclear what exactly you're looking for – or, if you don't even know that yourself, "too broad". – Izzy Feb 9 '15 at 12:37
1

As Angelo commented, you need something that scans from the outsize: GRC's ShieldsUp.

It scans your ports from the outside and tells you if they are open, closed (better) or stealth (best) + advice for first time users, full explanations of your results. Here's the results for scanning my file sharing ports:

enter image description here

I just used it last weekend to make sure that my SIP ports were not detectable from the outside.

Use the buttons at the bottom of the second page to scan specific port ranges:

enter image description here

(or specify ports yourself for the bottom two buttons).


It also lets you scan for a vulnerability where router manufacturers have set open uPnP to the outside - an absolute no-no.

  • 1
    thanks, the tools on that website are useful and i just found out that my problem isn't about closed ports. – user6306 Feb 9 '15 at 12:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy