GNS3 on an USB key

From WikiGNS3

By Jose Sen.

Introduction

Now GNS3 can be installed in an USB key, follow carefully these steps to be able to run GNS3 on any machine, with the only need of an USB port.

Limitations: GNS3 needs the Winpcap driver, but only for Dynamips to access an Ethernet card on the host machine in order to send or receive packets from the local network. So, if you are planning to create an topology without a LAN connection, you really don’t need to have Winpcap installed.

Steps

1. The first step is to have a clean USB key of at least 1GB.
2. Download Portable Appbase Suite
3. Execute the installation program.
4. Be sure to install it in the Root directory of your USB device.
5. When the installation is completed, go to the USB Root directory and start the following program: StartPortableApps.exe

You have installed the Portable Application Launcher and any portable application will appear like an option in the blank panel. Now you can install GNS3 on the USB key.

1. When GNS3 installation program start and you reached the "Choose Components", uncheck Winpcap 4.0.2 and proceed next.
2. On the next window you will be asked to select a destination folder, browse to find the directory \PortableApps\GNS3\ witch is in the USB drive. Proceed with Install.

Now GNS3 is installing in the USB drive. This may take a few minutes depending on the type of your USB drive. Once installed you can restart the portable application menu (StartPortableApps.exe). GNS3 should appears and you should be able to launch it from the menu.

Note: The reason why other items appears in this menu is that Portable Application software will include any .exe files. You need to be careful and not click on them if you don’t know what they will do.

From this point you can launch GNS3 and proceed as wanted, but don’t forget that Winpcap is not installed and no LAN communications can be done.

In the case you know that Winpcap is installed in the PC as result of another software has installed it previously (like Wireshark), you can launch GNS3 and use LAN connections without any problem. If not, I recommend to carry the Winpcap driver installer in the USB drive and install it as needed.

Drive letter mapping

Have in mind that every time you insert your USB drive into the PC, a drive letter for the USB drive will be assigned and this will cause troubles at the moment of executing GNS3.

I found two possibilities to solve this problem:

The first one is to review in the GNS3 Preferences all the references to the drive letter. If you are familiarized with GNS3 configuration, it should take little time. The only thing is that every time a reach a new PC we have to reconfigure GNS3.

The second possibility is to configure all GNS3 drive references to a drive letter that surely we are not going to find in any PC like letter Z:. The only task we need before running GNS3 is to map the real letter drive on the PC to our USB key. To accomplish this, insert you USB drive into the usb port, wait until the PC makes it ready to use, verify witch letter was assigned to the USB, in this example I will suppose that letter F: was assigned to the USB drive.

In a dos session window type the following command:

subst Z: F:\

This command will map the real F:\ drive to a virtual drive Z:.