The program is offered as a portable version and installer by its developers. Both versions offer the same functionality in all other aspects.

The software displays all listening ports, their protocol, process, process ID, associated services and company in the interface. This makes it relatively easy to identify specific ports directly in the program interface. Especially the associated services column can be helpful in identifying the responsible Windows services.

A right-click on a row opens a context menu with additional research options.

• Locate the executable file – Opens the folder that contains the process executable.
• Terminate this process – Terminates the process directly. May only be temporary if the process restarts automatically.
• Process services – Displays all services that are linked to the process.
• Google… – Research the port, process on Google.
• Wikipedia… – Research the port, process on Wikipedia.
• Usage statistics of this port – Look up statistics
• Port authority database – Provides information about most ports.

The menubar on top links to additional tools, commands and references. The tools menu links to Windows apps like the Services managements interface, the Task Manager, Registry Editor or Local Security Settings. Commands can run the netstat command to display all open connections, the task list and the system’s environment variables.

Internet references finally links to essays and white papers about ports and online security. Linked there are for instance BlackViper’s excellent website that is offering services configuration suggestions, lists of common port numbers or a Microsoft guide on how to configure a firewall for domains and trusts.

It is furthermore possible to display a short summary, and to export the current port list in detail. CloseTheDoor offers everything that one could hope for when analyzing open ports on a Windows machine. It is a solid alternative to CurrPorts. The software is compatible with all recent versions of the Microsoft Windows operating system. It tested fine on a 64-bit Windows 7 test system. Downloads of the portable version, installer and source code are available at the project website over at Sourceforge.

Installation?

Fortunately your distribution should come with the netstat command pre-installed. To check this, open up a terminal window (that’s where you will use netstat anyway) and issue the command which netsat. This command should return something like /bin/netstat. That will tell you that the tool is installed and where the executable is.

Usage

Because netstat offers such a variety of options, it might be best if I first list some of the more useful options.

a: Shows the state of all sockets and routing table entries.

c: Display information continuously.

d: Show the state of all interfaces that use DHCP.

e: Show extended information.

g: Show the multicast group membership information for both IPv4 and IPv6.

i: Display a table of all network inferfaces.

l: Limit statistics to a defined interface.

M: Show multicast routing tables.

n: Shows network addresses as numbers instead of the default symbols.

p: Show address resolution tables.

P: Limit statistics to a defined protocol.

r: Show all routing tables.

t: Show TCP connections.

u: Show UDP connections.

v: Use verbose mode for output.

So let’s take a look and see how these can be used together.

netstat

By itself (no options) this command prints out generic statistics of the host you are currently connected to.

netstat -an

This command will display all connections to the host, including source and destination addresses and ports, and displays them as numbers.

netstat -rn

This command will display the routing table for the host in numeric form.

netstat -r

This command will display your routing table for your host.

netstat -natp

This command will display active TCP connections in numerical form.

netstat -t –listening

This will show you all tcp ports you host is listening on.

Figure 1

netstat –statistics

This command will display various statistics for your host’s interfaces. Note that this command will display a LOT of statistics. A snippet of the output will look like that shown in Figure 1.

As you can see, this command will display quite a bit of information. On top of that you might need to pipe this command through the less command in order to see it more easily. That full command would look like netstat –statistics | less. Using it that way would allow you to use your arrow keys to scroll up and down through the ouput.

Final thoughts

Although not an exhaustive look at the netstat command, this will get you started and using this handy tool. Since there are so many switches and options to use with netstat, in order to cover them all, take a look at the netstat man page (issue the command man netstat) where you can see each and every switch explained.



The developers, who were working on uTorrent 1.9 alpha initially have decided to skip 1.9 and move forward to version 2.0 directly. The release notes mention the following feature additions in the Bittorrent client besides many fixes and changes.

• We’ve added UDP tracker support!
• uTP has been improved significantly over the previous alpha, with many bugs fixed and performance improvements. It’s no longer hidden in Advanced settings.
• The setup dialog has been overhauled to make it much easier to use and with a built-in speed test. It’s still not quite complete yet, but this will give you a good taste of what we’re up to with it!
• A new transfer cap feature has been added to track bandwidth usage, along with graphs to show your usage.

UDP trackers are a different protocol for tracker communication that uses significantly less processing power on the tracker end. It’s important for us to support this because trackers have limited resources, so this should allow them to support many more users with their current hardware and not crash under the load.

Support for UDP trackers could be beneficial not only for torrent tracker administrators and owners but also users as the performance gain could be noticeable on the front end as well.

uTP is an alternative communication method for BitTorrent traffic that allows the client to automatically regulate its bandwidth usage to avoid adversely impacting your internet connection. This will allow you or other users on the network to download their torrents without killing your connection without any additional setup required.

This is probably the most exciting addition for users who like to run uTorrent 24/7.

The transfer cap settings were added in response to various users who have ISP-mandated caps on how much data they can download/upload in a month. Now you can track your usage in MB (with a handy graph to visualize it) and even configure µTorrent to stop torrenting once the limits are exceeded. Currently, you can configure the time interval, the data cap and whether it should stop based on only download, upload, or both combined.
As a privacy notice, this traffic data is not sent back to us or anyone.

The transfer cap settings can be very interesting for users with bandwidth caps but it can also be useful for users who like to keep an eye on their bandwidth usage.

The setup guide on the other hand has been changed as well. Currently only test servers that are located in the United States are accessible which makes it unsuitable for users from Europe and Asia.

Users who want to upgrade their version of uTorrent to version 2.0 beta can do so by visiting the uTorrent forums.

What this means is that Fport will basically display all open ports and the applications that use them for their connection. This makes it very easy to find unauthorized connections by simply verifying the applications one by one.

Fport has to be launched from the command line or a batch script. It will display all open ports and their applications if it is executed without switches. The following switches are available:

/p (sort by port)
/a (sort by application)
/i (sort by pid)
/ap (sort by application path)

The output will look like this:

C:\>fport
FPort v2.0 – TCP/IP Process to Port Mapper
Copyright 2000 by Foundstone, Inc.
http://www.foundstone.com
Pid Process Port Proto Path
392 svchost -> 135 TCP C:\WINNT\system32\svchost.exe
8 System -> 139 TCP
8 System -> 445 TCP
508 MSTask -> 1025 TCP C:\WINNT\system32\MSTask.exe

392 svchost -> 135 UDP C:\WINNT\system32\svchost.exe
8 System -> 137 UDP
8 System -> 138 UDP
8 System -> 445 UDP
224 lsass -> 500 UDP C:\WINNT\system32\lsass.exe
212 services -> 1026 UDP C:\WINNT\system32\services.exe

The easiest way to work with fport is to save the output into a text document for further processing. This can be done with the command fport > output.txt which will create a text document with the name output.txt in the root directory of fport.

A similar application with a graphical user interface is Cports.