Discover what is blocking Network Ports - Firewalls etc

Posted on 2012-08-23
Last Modified: 2012-09-04

Occasionally I come across a user who says they cant connect to their network or the internet. Running all the normal network checks, disabling windows firewall & av, pings, tracerts etc often confirms that something is blocking the connection.

Does anyone know of a simple piece of software or a way to discover what is blocking a network connection. It would be great if there was a small prog that would check all ports and report their status and what is opening or more importantly closing them.

Any suggestions?
Question by:Winfix1
    LVL 5

    Expert Comment

    You could use Nmap for Windows

    Author Comment

    Thanks  Sjizzel. That could be a solution but it looks complex. How would I do what I want with this tool?

    LVL 5

    Expert Comment

    LVL 38

    Accepted Solution

    I am assuming you do this as a business to take care of home users to small business users.

    EVERY NETWORK is different, and as such will require different ports.

    The only way to determine if app ports are open or closed is to use a port scanner (yes a hacker's tool). Not all hacker's tools were created for malicious use. This is one of them.

    So, here we go:

    There is a port scanner for home use to test security. It's called Shields up:

    Internal networks and individual ports, I don't use telnet. Instead I use portquery:

    For Medium Business to Enterprise businesses, I wouldn't be caught dead without Solar Winds Networking tools. This is a modular set of tools to help you overcome the most difficult and insane networking challenges.

    Author Closing Comment

    Some good suggestions here.

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