Frequently Asked Questions


What is The DIMES Project?
DIMES is an academic software project held in Tel Aviv University. It's aim is to measure the internet through the use of thousands of agents which are being installed on home PC's by the DIMES volunteers.


How can I participate in the project?
All you need is to download our Agent and install it on your computer. Once the Agent is running you're on the hook :)


How does it work?
Once the Agent is running it is getting a script from our server which is telling it which IP Addresses to measure. For now, The Measurements can be done as TRACEROUE or PING in two Internet Protocols: UDP and ICMP.
We are planning on adding more kinds of measurements (for example, in the TCP Protocol).


What do I need in order to run the DIMES Agent?
A computer, The AGENT Installation file and a JAVA RUNTIME ENVIRONMENT from Version 1.5 and above.


How Much it will cost me?
Nothing. The Agent's software is free. DIMES is an academic project for research purposes - we are not making money from it.


How can I check my Measurements Statistics?
Easily. Just go to the Volunteer Statistics page and insert the user name you gave during the process of registering your Agent. From Agent Version 0.5.0 you have a a Personal Statistics Window in the Agent itself.


Does the DIMES Agent is over loading my system?
Unlikely. The Agent was designed to be a light weight software with a small system foot print. If you want to run it in the lightest way run it in a service mode.


What are the different modes of the DIMES Agent?
The DIMES Agent can run in one of 2 modes:

  1. Agent Mode: This way the Agent is running with a full interactive user interface. Search for the small cactus icon in your taskbar (for Windows users), double click it and you'll see the user interface, including the graph of your connections.
  2. Service Mode: This way the Agent is running in the background as a system service with no interactive user interface. The service foot print is very low, even trivial and it can still run when the user is logged off.


How can I be sure that DIMES is running in my machine? (Windows Users)
Depends of the running mode:

  • Agent Mode: You should see a little Cactus icon in your System tray (lower right corner of the screen). Click the icon and you will see the Agent's user interface.
  • Service Mode: Open the Windows Services Manager (Start -> Control Panel -> Administrative Tools -> Services) and check for Dimes Agent under the "Name" column. Check in the "Status" column - if it says "Started" it means DIMES is running in Service Mode.


I am trying to run the Agent and I am keep getting a warning which says that another instance of DIMES is already running. What is happening?
Probably the service is running in the background, and since that no more than one instance of DIMES is allow to run you can not run the Agent in the the Agent mode. You should stop the service either from the Windows Services Manager (see previous question) or from Start -> DIMES -> Stop Service and than start it again in a user interface mode (Start -> DIMES -> Start Agent). Once the Cactus is in your system tray (see previous question) - the Agent is running.


Agent 0.5.2 looks different! Where did the green buttons go? Agent 0.5.2 adds the ability to enable or disable the skins engine that is responsible for the "toxic Green" look that you are used to. By Default, the skins engine is disabled, and the Agent looks like any other program on your computer. If you'd like to enable the skins, look under Agent->Properties-Settings for the "Enable skins" checkbox. Once you enable that you'll have a choice of four different skins to choose from for the Agent, including the original "Toxic Green"


Using Agent 0.5.2 on Vista the graph doesn't seem to work. What's happening? Windows Vista has a mechanism called User Access Control, or U.A.C. which allows users that are not Administrators to run programs with administrative privileges. Since the Agent must open a couple of low-level ports to accomplish it's tasks, it naturally requires Administrative privileges to work. For users who are always logged in as Administrators, this is not a problem. And uses who are not Administrators, and have U.A.C. installed will get prompted to input the Administrator password. However, in a situation where:

A. The User is not and Administrator AND

B. U.A.C. is disabled AND

C. The Agent is not running as a service

There may be some situations when the Agent may not work properly.

The best way to avoid this is to install and run the Agent as a service. Which is the recommended way of running for Vista users.


linuxAgent.sh keeps giving me an Error about JAVA_HOME. What should I do?
The Linux Agent uses a variable called JAVA_HOME to point to where the Java runtime files are located.
In order to set the JAVA_HOME variable follow this procedure:

1. Locate the directory where your java binary file is located. A good way of doing that is by typing "which java" in the command prompt.

2. The directory for JAVA_HOME is the directory that contains the bin directory of the Java installation. So if you type in "which java" and the system answered "/usr/local/jdk_1.6.3/bin/java" then you need JAVA_HOME to point to "usr/local/jdk_1.6.3" Write that down.

3. Go to the /usr/local/DIMES/scripts_linux directory and locate agent.sh open it with your favorite text editor. NOTE: you must be root to do this.

4. In the script, insert the line
JAVA_HOME="/your/directory/here" where the directory is the one you wrote down in step 2. Make sure you put this line near the top of the script, right above the line that reads "CURRENT_DIR"

5. Save the file and run it. This should fix the error. You should only have to do this once.


How can I check if my Firewall blocks the Agent's measurements?
3 ways - it is recommended to check all of them:

  1. Blocking Test:

    1. Assure the Agent is running in an Agent mode and open the graphical user interface (see previous questions).
    2. In the Agent's toolbar (upper left corner of the window) go to Agent -> Prpoperties -> Network
    3. Look in the right lower corner under Blocked status:

    4. Press the "Check Blocking" button. The caption of the button should be changed to "Checking":

    5. If one - or both - of the little globe icons is changing his color to red it means that the relevant protocol is blocked in your system:

  2. Agent's Messages: Look in the messages window of the Agent. If you see any red font messages which alert about I/O or server problem - There is probably a connection problem.

    If you see many "Destination didn't reply" messages:


    And you can't see any "Recieved packet" message:


    It probably means that your firewall doesn't allow getting TRACEROUTE/PING answers.
  3. After few minutes of the Agent's run switch to the graph window. If you don't see any nodes in the graph, except of one - your machine - it probably means your firewall is blocking the answers of the TRACEROUTE/PING measurements.

IF any of this is happening please check in your firewall manual how to allow TRACEROUE/PING measurements from your machine.