In this article, we will highlight some of the possible causes that might lead to using netstat to detect open ports on Windows Firewall, and then provide possible solutions that you can use to try to resolve the issue.
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You can use netstat -b -the real -o. This tool provides a document of all open ports and their associated processes. -O specifies the process ID, which you can look for in the task manager or optionally in the process tab. To complete this approach, just enter taskkill / PID xxxx.
Learn How To Use Netstat To Determine Which Firewall Port To Open When Troubleshooting Windows XP Firewall.
How do you check which ports are open in Windows Firewall?
Run Command Prompt.Run netstat -a -n.Make sure the correct port is listed. If yes, it meansthat the server usually listens on which port.
- Brian Posey
Released: Oct 21, 2007
How many times have you sold simple software trying to figure out why it doesn’t work with your client’s Windows XP firewall? The solution to this problem is simple: just open the firewall port that is used next to the application. The trick is to know which port to open. This is usually not a problem if the application is using a known port; on the contrary, many applications rely on obscure and little-known ports. With over 65,000 TCP concatenated with UDP ports everyone to choose from, guessing the correct port is not the best option. Fortunately, no. There is a little known trick that you can use to determine which port on a firewall a manager is using.
I could easily write a complete article on the syntax of my ownabout the command line tool. But netstat, for this purpose I’m really going to discuss the switches required to know which firewall ports the application is using. To find out more about the other available switches, just type NETSTAT /? at the command line. You can also view the Netstat documentation on the Microsoft Windows Professional exp documentation page.
There are three switches in
that you can use to determine the number of ports on the firewall. The / A option causes Netstat to display the screen of all connections and listening locations. The / N switch forces Netstat to display the addresses of IP volumes and ports in numeric form. Finally, its / O switch displays the process number, which is comparable to other ports.
Depending on the number of running processes, the output of a particular command can fit on one panel for a long time. Therefore, to troubleshoot Windows XP Firewall, we recommend that you successfully redirect the output to a file. You can bring the idea to life by adding a proof greater (>) and a file for the end name of the command. For example, the following commandredirects the output to a file named C: NETSTAT.TXT:
netstat / a / o / n> c: netstat.txt
Figure A below shows the approach and content of a kind of NETSTAT.TXT file. Remember that in the human brain, the contents of a file are always different on every PC and you need to use an application for which you usually need a port number in order for the file to be useful.
Figure A. The Netstat control can be used to identify the most commonly used firewall ports.
In the Netstat command line output, you can see the IP addresses as well as the port numbers that appear in the Local column of all addresses. Port numbers are separated from the IP address by colons. For example, the local help for one of the functions shown in Figure A is 184.108.40.206:139. This means that the registration takes place through the IP address 220.127.116.11 and record 139.
port numbers to real applications
How do you make sure firewall ports are open?
Usually right-click the Start button.Click on the search button.Enter Windows Firewall.Click Windows Firewall.Click Advanced Settings.In the left frame of this window, click Inbound Rules.In the correct window frame, click New Rule….Click Port.
If you look at this output, you will find that Netstat does not list your applications. Even so, the lists in the last column deal with the identifier (PID) associated with the appendedusing the connection. To determine which application is using a port, you must map applications to PID numbers. To do this, select CTRL + ALT + DEL, open the main Windows Task Manager and click here the Processes tab. As shown in Figure B, this tab lists the actual processes in use, but note that it does not list the PID link numbers.
Does netstat show all open ports?
By default, Netstat displays all TCP and UDP connections and their corresponding status, regardless of whether you specify any options. Note that this excludes ports when using ringtone mode. Listening ports are generally ports that a program responds to, but to which valuable clients are not necessarily connected.
B: By default, Windows Task Manager lists processes, but no rough numbers.
To resolve this issue, clearly choose the Select Columns command from the View menu of the Manager. In the Select Columns dialog box (see Figure C), select the PID check box and click OK.
Figure C. Check the PID box, then click OK.
As shown in Figure D, the PID number is now displayed in Windows Task Manager. Before that, I showed you a process in which many use the IP address and login 18.104.22.168:139. In Figure A, you can see that the PID assigned to this IP address is then port number 4. In Figure D, you can see that PID 4 is the systemth process. As part of Windows XP firewall troubleshooting, when determining which applications are targeted to ports, scroll down until you find the replacement IP and port number that actually matches the PID assigned to the application. In this step, you determine which port number the application really wants to use and which means that you open the required port in that firewall.
Figure D. The PID column tells you that process.ID has been positively assigned to a process.
You must use this method to select the port generated by the application. Note, however, that Windows can run processes differently under different user accounts. Therefore, if the target of your process is definitely not listed, clients may need to check Show processes from all users in Task Manager.