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Thread: Tcp/ip

  1. #1
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    Tcp/ip

    Subject: TCP/IP
    Shields Up scan gave me this result:


    Port Authority Database

    Port 80

    Name:
    http

    Purpose:
    World Wide Web HTTP

    Description:
    This is the primary port used by the world wide web (www) system. Web servers open this port then listen for incoming connections from web browsers. Similarly, when a web browser is given a remote address (like grc.com or amazon.com), it assumes that a remote web server will be listening for connections on port 80 at that location.
    How do I close this port? I have a cable modem with Wi-Fi, it's a ubee modem.

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    Port 80 is indeed the standard port that web servers use to serve up http requests.

    To check if Port 80 active do the following:

    Open a command prompt and type "netstat -anop TCP" without the quotes.

    This will list all the open TCP ports on your system. There will probably be lots, but don't worry, many are used by Windows or by other software to communicate to other modules. Scroll up the list, looking at the second column on the left. You are looking for an IP address ending in :80 (the TCP/IP port number). If you find that, port 80 is open and you see anything other than 0.0.0.0 to the right of the port 80 entry, something or somebody is connected to it.

    It is very rare for residential systems to open it and in almost every circumstance requires manual actions to do so - you would almost certainly know if you had opened it.
    Last edited by Tinto Tech; 2011-11-22 at 08:59.

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    Port 80 is also the standard port for a web browser to connect to the internet. If you do anything on the internet why would you want to close the port?

    Joe

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    If you really want to see what is being done with TCP/IP and UDP ports, download and run Nir Sofer's CurrPorts utility. But you may well end up none the wiser.

    It may also be worth pointing out that some of Steve Gibson's views on computing matters are often criticised by other knowledgeable technical people...
    Last edited by BATcher; 2011-11-22 at 09:17.
    BATcher

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    Tcp/ip

    Quote Originally Posted by Tinto Tech View Post
    Port 80 is indeed the standard port that web servers use to serve up http requests.

    To check if Port 80 active do the following:

    Open a command prompt and type "netstat -anop TCP" without the quotes.

    This will list all the open TCP ports on your system. There will probably be lots, but don't worry, many are used by Windows or by other software to communicate to other modules. Scroll up the list, looking at the second column on the left. You are looking for an IP address ending in :80 (the TCP/IP port number). If you find that, port 80 is open and you see anything other than 0.0.0.0 to the right of the port 80 entry, something or somebody is connected to it.

    It is very rare for residential systems to open it and in almost every circumstance requires manual actions to do so - you would almost certainly know if you had opened it.
    Thank you, I didn't see anything you mentioned, so I assume I'm ok. I don't know how reliable that test is.

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    Hi qwest, have a look here http://www.canyouseeme.org/
    George's PC Specs. / Laptop. Desktop.

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    As Joe said, if you want to close port 80 you might as well unplug from your ISP since that is your "Internet" port. That's how you got to this website.

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    I think we need to be careful here in our definitions of local and remote ports.

    Port 80 is used by web servers, not by the browser. It is the outgoing port for http requests - your web browser will use a local high port to connect to the remote port 80 on the web server. Port 80 on the local machine should rarely be opened.

    As an example, see the two attached screen grab using the nirsoft tool recommended by BATcher:

    local ports low.JPG

    Low ports - notice no port 80 open on this machine

    local ports google chrome.JPG

    High ports - Google chrome opened high local ports to connect to remote port 80 at various http web servers.



    If I use the Shields Up service that the OP used to scan his system I get the following:

    shields up profile.JPG

    Notice Port 80 is closed to the outside world, due to both my firewall and the port not being open.

    Now, if I enable the XAMPP webserver on the local machine:

    port 80 xampp webserver open.JPG

    see how Port 80 is now open on the local machine using the nirsoft tool. Shields up still reports this is closed to the outside world becasue I have not port forwarded this through my firewall.

    So having a closed outgoing port 80 on my machine does not stop the browser from connecting to port 80 on the remote server using a high local port and it does not disconnect one from the internet.



    The OP was using the Shields Up service to probe his system. It responded that it found port 80 open. Most likely this was port 80 for the web interface in the modem/router rather than on his machine.

    Using either the netstat command line tool or the nirsoft tool will reveal if port 80 is open on the machine. The nirsoft tool gives easier to use info on the program that might have opened it.

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    For the OP, just think, first thing ShieldsUP hits on your end is what its measuring, if its the modem/router, its the modem/router, not your computer. Its testing your Internet I.P. address responses.

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