Moo0 ConnectionWatcher is another program that can display a detailed list of those programs. The application is available as a portable program and installer, and will display all open connections on startup.

The interface looks similar to the file monitoring application by the same developer which I reviewed yesterday.

Each connection is listed in its own line, with detailed information about the protocol, process id, process name, local and remote port and data that has been received.

A right-click on any entry opens a context menu with options to close or kill the process, locate the program on the computer’s hard drive, disconnect the connection or open the program’s properties.

The status bar displays statistics about the number of open connections, the protocol, and the data that is currently received and sent.

Besides the option to display the current connections, it is possible to view a log with past connections as well. All connections are sorted by date and time, with options to save the log to the local computer system for future reference.

The connections in the current and log view mode can be sorted by all columns, for instance by application name, port number or bytes received.

The View menu at the top can again be used to change the update frequency of the data and the number of log entries that the program stores at the same time.

Moo0 ConnectionWatcher is a handy program to monitor Internet and network connections. It is not as lightweight as CurrPorts though, and could use advanced features like filtering, alerts and notifications, references and web searches.

The program is compatible with recent 32-bit and 64-bit Windows operating systems. It was tested on Windows 7 Professional 64-bit.

Currport lists Internet connections of all applications and services on the system, which can for instance be used for troubleshooting purposes, identifying if an application has a “phone-home” feature implemented, or if malicious software managed to establish an Internet connection.

The program displays the information right after startup, making it one of the easiest to use programs in this app category.

currport internet connections

The software program lists the process names on the left. Processes include programs started by the user, system processes, services, and automatically started processes. Programs are the easiest to identify, as their name usually contains part of the program name. Firefox.exe, or chrome.exe should be self-explanatory.

Currports displays lots of information about each connection, including the protocol used, the local and remote address, the process creation date, username that the process was started from and the window title.

The remote address and host name columns display information about the remote computer systems. This makes it relatively easy to spot connections that have not been initiated by the user. It is a good precautionary method to regularly fire up Currports to check the open connections of the computer system to ensure that no connections with (possible) malicious intent are open.

Currports in addition to that lists all listening ports that are open on the system. Those are usually opened by Windows services, and should only be open if they are needed on the computer. All services that open ports but are not needed should be closed to increase the protection of the PC.

The best option is usually to research the local port name in combination with the operating system, to find out which service is responsible for the open port. The service description then reveals if the service is needed on the system or not. A windows 7 PC without a homegroup or local network connections may not need the Function Discovery Resource Publication and SSDP Discovery services, as those are only used to publish information about the computer, and discover other computers in the network.

The main advantage of Currports over comparable solutions, including the netstat command line tool, is the ease of access, and the exporting capabilities. Newer versions of the program can even close one or more connections over the command line.

Currports is one of those small tools that makes the life of a system administrator, computer technician or end user so much easier. The program can be downloaded from the Nirsoft website.

A port basically allows communication to or from the device. Characteristics are a port number, an IP address and a protocol type. This article will give you the tools at hand to identify and evaluate the open ports on your Windows system to make a decision in the end whether they can or should be closed or left open.

Software programs and tools that we will use:

• CurrPorts: Available for 32-bit and 64-bit editions of Windows. It is a port monitor that displays all open ports on a computer system. We will use it to identify the ports and the programs that are using them.
• Windows Task Manager: Also used to identify the programs and link some ports to programs.
• Search Engine: Searching for port information is necessary for some ports that cannot be identified that easily.

It would be an impossible task to go through all of the ports that are open, we will therefor use a few examples to enable everyone to understand the process and go on from there.

Fire up CurrPorts and take a look at the populated main area.

The program displays the process name and ID, local port, protocol and local port name among others.

The easiest ports to identify are those with a process name that corresponds to a running program like RSSOwl.exe with the process ID 3216 in the above example that is listing on the local ports 50847 and 52016. Those ports are usually closed when the program closes.

The more important ports are the ones that cannot be linked to a program right away like the System ports shown in the above screenshot.

There are a few ways to identify the services and programs linked to those ports. There are other indicators that we can use to discover the services and applications besides the process name.

The most important ones are the port number, the local port name and the process ID.

With the process ID we can take a look in the Windows Task Manager to try and link it to a process running on the system. To do that you need to start the task manager (press Ctrl Shift Esc). Click on View, Select Columns and enable the PID (Process Identifier) to be shown. That’s the process ID that is also shown in CurrPorts.

Now we can link process IDs in Currports to running processes in the Windows Task Manager.

Let us take a look at some examples:

ICSLAP, TCP Port 2869

Here we have a port that we cannot identify immediately. The local port name is icslap, the port 2869, it uses the TCP protocol, has the process ID 4 and the process name system.

It is usually a good idea to search for the local port name first if it cannot be identified right away. Fire up Google and search for icslap port 2869 or something similar.

Often there are several suggestions or possiblities. For Icslap they are Internet Connection Sharing, Windows Firewall or Local Network Sharing. It took some research to find out that in this case it was used by the Windows Media Player Network Sharing Service.

A good option to find out if this is indeed the case is to stop the service if it is running and refresh the port listing to see if the port is not appearing anymore. In this case it was closed after stopping the Windows Media Player Network Sharing Service.

epmap, TCP port 135

Research shows that it is linked to the dcom server process launcher. Research also shows that it is not a good idea to disable the service. It is however possible to block the port in the firewall instead to close it down.

llmnr, UDP port 5355

If you look in Currports your notice that the local port name llmnr uses the UDP port 5355. PC Library has information on the service. It is referring to the Link Local Multicast Name Resolution protocol which is related to the DNS service. Windows users who do not need the DNS service can disable it in the Services Manager. This closes the ports from being open on the computer system.

Conclusion:

It is not always easy to identify ports and the services or applications they are linked to. Research on search engines usually provides enough information to find out which service is responsible with ways to disable it if it not needed.

A good first approach before starting to hunt down ports would be to take a close look at all started services in the Services Manager and stop and disable those that are necessary for the system. A good starting point to evaluate those is the services configuration page at BlackViper.

The network connection data that is displayed by Connection Monitor is basic but useful for a quick overview of all network connections. The program itself lacks information that are displayed in Curr Ports, most notable the process ID and process that are using that network connection. It is therefor more difficulty to identify the running processes with Connection Monitor.

Curr Ports (and Open Ports as well) is therefor the better alternative for users who would like to identify the processes that use the open network connections. Connection Monitor is a free download at the developer’s website. No compatibility information are displayed on the website or in the application. It worked fine on a Windows XP SP3 test system.

Netlimiter 2 Monitor is a sweet software that displays all open processes and applications on the system detailing their incoming and outgoing bandwidth along with ports, IP addresses and process numbers. That’s basically the same amount of information that my previous favorite Currports is displaying.

The first difference is that Netlimiter Monitor has a history function where it is displaying which applications connected to the Internet before on your system. Great for quickly checking out if an app is among the list that should not be there.

It’s definitely a great application if you want to evaluate the bandwidth usage of a process or software. I used it to keep an eye on Skype to see if my computer was used as a Skype supernode.

The Pro version of Netlimiter adds some interesting functions like Traffic Shaping, Network support, Network Tools like Whois and Traceroute, Remote Administration and Advanced Rules.

In addition, CurrPorts allows you to close unwanted TCP connections, kill the process that opened the ports, and save the TCP/UDP port information to an HTML file , XML file, or to a tab-delimited text file.

CurrPorts also automatically marks suspicious TCP/UDP ports with pink color. These are usually owned by unidentified applications (Applications without version information and icons)

#only 36K, freeware, no system changes, download and run
#runs on all windows versions but older versions show less details

Update:

Nir Sofer has updated the application constantly ever since we first reviewed it here on Ghacks. Users can now select to run a 32-bit or 64-bit version of the application. CurrPorts at its core has remained more or less the same though.

You can start the portable application directly after you have downloaded and unpacked it on your computer. The program then displays a list of all running processes in its interface. The information are updated in realtime, which means that you can use the program to see if applications that you install or start are trying to phone home or opening ports on your system.

The second option that you have is to check for open ports on the PC that should not be open in first place. You can improve your computer’s security by closing those ports as it reduces the number of attack vectors that attackers have. It is still necessary to research how ports are closed, as this is something that CurrPorts does not help you with.

Windows users can download Currports from the official Nirsoft website. Download Currports