Network Testing and Emulation Solutions
The Various Techniques Cookbooks provide miscellaneous examples of how to perform various network configuration tasks. Each is a set of step-by-step instructions intended to help build your familiarity with network configuration in Linux and Windows.
Please contact us at support@candelatech.com if you have any questions.
| In cases where is is not convenient to use an existing management network, LANforge WiFi systems can be configured to provide their own WiFi management network. This may be especially useful when testing in environments where LANforge needs to be moved around or where you have no good access to existing management LANs. This example assumes that you already know how to create and configure VAP and Stations in LANforge. | |
Configure LANforge for Auxiliary Management.
Connect LANforge systems through the normal management LAN for initial configuration. The resources should be visible in the management tab
In this case, we are using wiphy0 for the Aux-Mgt interfaces. On the manager system, configure wiphy0 to be on the desired channel, create a virtual AP on wiphy0, and configure it appropriately. The Aux-Mgt checkbox should be selected, a static IP should be assigned, and an appropriate SSID configured. The AP Aux-Mgt port will automatically serve DHCP and will try to NAT and route packets to the wired Management interface.
On the other resources, configure the wlanX interface to connect to the AP on the manager system, and select the Aux-Mgt checkbox.
The Port-Mgr tab should look something like this when the Aux-Management interfaces are configured.
To test that it works properly, you can now remove the wired Manament port connection and wait about 1 minute for the old connection to time out and re-connect to the Auxiliary Management port. Or, just reboot systems with the wired ports unplugged and they should be discovered on the Aux-Mgt ports promptly.
| Here are some techniques for finding and setting IP addresses on Microsoft Windows using the Control Panel and the command line. |
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Find the IP Address of the Windows PC. There are two methods you can use:
Using the Control Panel:
Click Start, Run, control, [enter]
Search and select Network Status and Devices
We click on our device, Ethernet 3:
Find and/or set the IP address: from Status, click Properites
double click TCP/IPv4
you will see and can change the IP address.:
Various DOS commands to find the IP addresses on the system:
ipconfig and ipconfig /all
netsh interface ipv4 show address
Resetting your DHCP address via command line:
ipconfig /release
ipconfig /renew
| Here are some techniques for finding MAC addresses on Microsoft Windows using the Control Panel and the command line. |
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Find the MAC Address of the Windows PC. There are two methods you can use:
Method 1: use the Control Panel
Click Start, Run, control, [enter]
Search and select Network Status and Devices
We click on our device, Ethernet 3:
Click Details...
Details will show the MAC address (physical address):
(Suggested) Set the IP address if you have not already.
For more information see Finding Windows IP Address
Method 2: use the DOS command-line. You want to correlate the IP address and MAC address of the Windows ethernet port:
Click Start, Run, and type cmd, and press [Enter]
Show interfaces by name with the command: netsh interface ipv4 show addresses
(Optional) if you do not see results, you might need to start the network autodiscovery service: net start dot3svc
(Optional) Depending on the edition of Windows, the command netsh lan show interfaces will display mac addresses.
Show mac addresses with: getmac /v /fo csv
(The CSV formatted command of the command ensures that we will see the entire name of the interface which can be trimmed short in the default output format.)
These commands will make it easier to copy using notepad:
netsh interface ipv4 addresses > ifnotes.txt getmac /v /fo csv >>ifnotes.txt notepad ifnotes.txt
Now you can easily copy the values:
| Here we review DOS window settings that will help you to work faster. |
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Customizing DOS Window Settings starts by right clicking the Start Menu
Type in cmd and hit 
To get to your DOS window faster, you can pin it to your task bar. Right click the task bar CMD window icon and select Pin this program to taskbar
On the DOS window title bar, Right click and select the Defaults menu item
Select the Quick Edit Mode setting. This allows you to highlight text in the window easily.
In the Font tab, select a slimmer TrueType font, like Consolas or Lucida Console, and set the font size to 10
In the Layout tab, change the Window Size to 132 columns and 56 rows
Click OK to save. The next DOS window you open will appear with your customized settings.
| Use this technique to inspect your DOS environment variables for specific strings using findstr. |
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Follow this example to see if perl is installed and your %PATH% environment variables is updated. First, open up a DOS window:
Type in the DOS Window: echo %PATH% | findstr /i perl
If perl is installed correctly, you should have it in your path.
You can also use this technique to find any environment variable. E.G., find if you have a temporary directory set:
set | findstr /i temp
| Lots of tasks, like scripting, can be done over SSH from your Windows desktop. Here are a few steps to help you customize your PuTTY terminal to work faster. |
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Configuring a PuTTY Session
When you double click on the PuTTY icon and it launches, you can start customizing your session preferences. We'll name this session jedtest
Let's default the window to something large, like 120 columns and 56 rows.
The Fixed font can be replaced with the Consolas font.
Let's turn on TCP Keep-alive and set IPv4 as the default networking protocol.
We login to LANforge resources with user lanforge
Generating a SSH keypair is not difficult. Let's enter the path to our public key file.
We have done our PuTTY config. Now back to the top Session screen, and click Save
Configure Pagent with your public key
Create your own public ssh key.
For more information see WinScp Net
Start Pagent. Configure it to load on startup.
In the System Tray you will see the Pagent icon.
Right-click the Pagent icon and click Add Key to select your key
You will need to provide your pass-phrase to load your key
We see a loaded key
Here is our key, we will view the .pub file to copy out the public key.
In a putty window you will log into your LANforge server and edit /home/lanforge/.ssh/authorized_keys
Copy the text and place the "Comment" section at the end when you paste it into your ssh
Here is the public key string, with newlines and spaces removed. The Comment text goes at the end.
Check the permissions of the authorized_keys file. You might need to use the command
chmod 600 authorized_keysto correct the permissions.
The next time we load the jedtest PuTTY session we should not be prompted for our password.
| The automatic driver install process for Windows 7 might automatically install a Microsoft Windows version of the Arduino Mega driver. This is not the driver LANforge expects. These instructions will guide you how through uninstalling an old driver and installing the new driver. | |
You want to install the windows version of the LANforge Server beforehand.
For more information see Installing LANforge Server on Windows
This process requires you to operate the Control Panel as Administrator. Some patch-levels of Windows 7 have secured this. A useful work around for this will be discussed shortly.
Getting to the Device Manager
Start by clicking the Start Menu and typing control 
Select Hardware and Sound
Select Device Manager
In the Device Manager window, right-click on the computer and select Scan for hardware changes
There will be an Other devices→Unkown Device entry. Right-click on it. If the options menu only gives you Scan for hardware changes or Properties, you might need to restart your control panel as Administrator, that is discussed next.
If you have recently removed a driver, you might need to reboot your Windows system for it to complete the driver installation process.
Using the Run as Administrator option to start the Control Panel in administrator mode.
This works best with a CMD window pinned to the task bar. You can do that using Start Menu→ cmd
Then right-click→ Run as Administrator on the cmd taskbar icon
Repeat your navigation steps to get to the Device Manager
If you find a previously installed driver, uninstall it. Especially if this is labeled Windows Arduino Mega
Right-click → Uninstall
Select Delete the driver software for this device, and click OK
Right-click on the computer, and select Scan for Hardware Changes
You might need to un-plug and plug-in your Attenuator.
If the right-click options menu does not allow you to change drivers, reboot your system.
Depending on your version of Windows, you might not find the driver file using the Browse my computer choice, you might find it using the Automatically Search choice.
In Device Manager, you want right-click on the Unknown Device and select Update Driver Software...
Click on Let me pick from a list of device drivers on my computer
You see a list of drives. Click the Have Disk button:
Enter C:\Program Files (x86)\LANforge-Server. Click OK.
Browse to C:\Program Files (x86)\LANforge-Server and click Next
This is not a signed driver. Please confirm the installation.
You will see the Update Driver Software confirmation. Click Close.
You should not need to reboot your system in order to run the Attenuator.
| LANforge computers on Intel hardware are typically installed with a full Linux desktop. You can use the LANforge GUI, do traffic sniffing, open terminal windows, and office software to look at report data over remote desktop. LANforge computers are pre-configured with RDP and VNC desktop services. |
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From your Windows Start Menu, type "remote" and Remote Desktop Connection should be an option.
If you are using the Start→Run menu, type mstsc
If you want to create a desktop shortcut, explore the folder C:\windows\system32 and right-click mstsc.exe
Configure your connection:
Fedora version 24 and 25 have a bug in the vncserver triggered by xrdp. The effective way to use rdesktop on those systems is to select an Xorg session for connecting (not a Xvnc session).
When connecting to Fedora 14-23 systems:
User Name: lanforge
You will not need to fill out the xrdp login screen.
When connecting to Fedora 24-25 systems:
Do not specify a user name, and select Always ask for credentials.
Select Xorg as the session type
Specify username lanforge and password lanforge
Local Resources
If your rdesktop session immediately closes, you might have hit the xrdp clipboard bug. If so:
For Windows Remote Desktop (mstsc.exe): unselect Local Devices→Clipboard
For Linux rdesktop, use the command: rdesktop -a16 -r cliboard:off -u lanforge [machine-name]
Disable remote audio settings
Disable local printers
Set Server authentication to Connect and do not warn
Connection quality can be 16-bit (millions of colors)
Click Connect to connect to the default desktop, the default password is lanforge
When you are DONE with your connection, you may close the Remote Desktop window. You will not be logged out. However, if you log in without setting the Username option, you will be logged into a new session alongside your old session. If you see this screen below, you are starting a new desktop session:
To reconnect to your previous desktop session, make sure you use the Username lanforge in your connection settings.
To logout of the desktop session, select System→Log Out from the top window of the Linux desktop.
| LANforge computers on Intel hardware are typically installed with a full Linux desktop. You can use the LANforge GUI, do traffic sniffing, open terminal windows, and office software using a VNC Viewer program. LANforge computers are pre-configured with RDP and VNC desktop services. |
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You can download a variety of viewers:
Check for viewer packages on your LANforge web page: http://192.168.1.101/
From your Windows Start Menu, type "vnc" and VNC viewer should be an option.
If you are using the start menu, it will be under either in All Programs > RealVNC or TightVNC
Double click the vnc icon and it will ask you for the IP address. You want to set the Encryption option to off because we presume you are connected directly to the LANforge.
VNC Viewer might warn you about connecting without encryption. This is a valid warning if you are connecting across public networks.
The password is lanforge.
You will see the LANforge Linux desktop. This is not the same desktop that is actually running on the console if you have a monitor and keyboard connected.
When you are done with your connection, you may close the VNC viewer window. You will not be logged out. When you connect using VNC viewer again, it show the current state of that desktop. connect you to the last used VNC session.
To restart the vnc desktop session, select you can issue either of these two commands. You start using ssh (PuTTY et. al.) to connect as lanforge to the LANforge machine, and:
sudo systemctl restart "vncserver@:1.service"
or
sudo vncserver -kill :1
| The native display protocol for Linux (and Unix) is the X Display Protocol. The Cygwin.org project provides Linux software that runs natively on Windows. You can run an X display server on Windows that accepts connection from LANforge. We will walk through setting up Cygwin and configuring an X display. |
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Installing Cygwin and the X display components
We will start at Cygwin.org and download the Cygwin installer.
Download setup-x86.exe or setup-x86_64.exe as appropriate. Go to your Downloads folder and double start the program.
Next
Next
Next
Choose a mirror that might be close to you, click Next
Now you see a the software selection screen, sorted by category. Some of these entries appear two or more times, because they belong to multiple categores. Try using the search box in upper middle above the software list to search for the packages listed below.
The items you want to search for are
Search for openssh and click the Skip property once to change it to the most recent version to set it to install.
xorg-server provides the X display system
xinit helps the X system launch
xlaunch is what you will drag to your task bar to launch your Cygwig X server
rxvt and rxvt-unicode are more useful terminals than the minterm program that Cygwin provides by default.
Click Next and let the installer finish the installation of the Cygwin packages. You will see a Cygwin Terminal icon appear on your desktop and new Cygwin icons in your Start menu.
Next we will right-click on the Cygwin Terminal icon and select Open File Location
In the Explorer window, scroll to find xlaunch.exe, and drag it to the Task Bar
Click the xlaunch icon on the task bar, and click Next
Next
Check Disable Access Control and add the option: -listen tcp. Click Next
Firewall, Click Allow Access
Now your X display service is running. You can check that it's running by clicking into the System Tray and seeing if the icon is there.
Launch the LANforge GUI from your desktop. Select a port from the Port Mgr tab. Notice how the Disp field has your laptop's LAN address. This is the display address the remote machine will display the Wireshark window to.
You will see WireShark
Resources and other Documentation:
| By default, your LANforge server and your LANforge client do not save the data on connection and port performance. When you configure the save destination for this data, you can use it with any other tool that can read a CSV file. |
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You can tell the LANforge server to save data to a directory locally on the
management machine, and you can configure your workstation running the the
LANforge GUI to save data to a local desktop folder. First, find the Reporting
Manager dialog by in the
Reporting menu, and select Report Manager the client.
Collecting data on your local workstation is very convenient if you can leave
the GUI running for the duration of your test scenario. The format of the data
here should be similar to the format of the data saved to the server directory.
The folders for collecting data are relative to the folder you start your
GUI from. If you type in lf_data that probably means
C:\Users\mumble\AppData\Local\LANforge-GUI\lf_data. You probably want to
put in a fully qualified path thats more intuitive, like
C:\Users\mumble\Documents\lf_data.
The Report Generator uses the local data files. In that dialog shows the
Report Input Directory field is a local folder where the CSV files
collect. The Save Reports to Directory field is where HTMl and PDF
files should collect.
If your test scenario runs longer than your GUI can be up, you can configure
the LANforge server to collect the data. The directory is relative to the
/home/lanforge directory, so if you enter lf_data, you would
find the CSV files in /home/lanforge/lf_data.
You can take a look at the data files easily. Here is a server data collection directory:
And using a utility like notepad, vi, more or less you can look at the file contents:
Importing the file into a spreadsheet like LibreOffice Calc is simple:
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You only need to separate on comma (,)
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Libre Office does not have a builtin formula to do this, but it has been discussed here. And the solution is a formula that looks like this:
=(A2/86400)+25569and then you format the column as Date.
There are a number of ways to collect an dort the data with shell utilities. The first utility to consider is cut, then awk. The first column of the endpoint file we are going to read is the timestamp, the 14th is the rx bytes.
$ head -n2 c201-A_1488414451.csv | cut -d, -f1 TimeStamp 1488414454125 $ date -d @1488414454125 Mon Dec 23 19:28:45 PST 49135
$ head -n2 c201-A_1488414451.csv | (while IFS=, read -a L; do echo ${L[13]}; done)
rx_bytes
33847640064$ head -n2 c201-A_1488414451.csv | cut -d, -f14 rx_bytes 33847640064
$ head -n2 c201-A_1488414451.csv | awk -F, '{print $14}'
rx_bytes
33847640064
head -n2 c201-A_1488414451.csv | awk -F, '{print $1 "\t" $14}'
TimeStamp rx_bytes
1488414454125 33847640064
It is a lot easier to do math with a perl script than a bash or an awk script. You can pipe things into perl or perl will read the last argument of the -ne switches as an input file.
$ head -n2 c201-A_1488414451.csv \
| perl -ne '@v=split(/,/,$_); print "$v[0]\t$v[13]\n";'
TimeStamp rx_bytes
1488414454125 33847640064
perl -ne 'BEGIN{$tt=0;@tstamps=();@rxb=();} \
{@v=split(/,/,$_); push(@tstamps, $v[0]); push(@rxb, $v[13]);} \
END{$dt=$tstamps[$#tstamps] - $tstamps[1]; $db=$rxb[$#rxb] - $rxb[1]; \
print "Time: $dt, Total:$db\n";}' \
c201-A_1488414451.csv
Time: 18959363, Total:1213399040
Not everthing you do in perl is going to be a one-liner. Here's an example of the same script as a more properly formatted perl file:
#!/usr/bin/perl
my $tt=0;
my @tstamps=();
my @rxb=();
while(<>) {
@v = split(/,/, $_);
push(@tstamps, $v[0]);
push(@rxb, $v[13]);
}
$dt = $tstamps[$#tstamps] - $tstamps[1];
$db = $rxb[$#rxb] - $rxb[1];
print "Time: $dt, Total:$db\n";
| Many LANforge ICE WAN emulator machines are embedded systems that lack display hardware. Installing an OS using only the serial console can be very inconvenient. The easy solution is to perform the installation on similar hardware that does have display hardware, and then move the drive to the embedded device. Here, we learn how to use Etcher on Windows to write a compressed disk image to an mSata drive plugged into a USB3 adapter. |
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Here we're using Etcher which handles compressed file system images without any trouble. There are other programs (like Win32 Disk Imagaer or dd for windows) but those are more complex to use.
Items we'll want:
30GB or larger mSATA drive
USB3 mSATA drive adapter
Download and install Etcher
Identify your drive in Control Panel → Hardware and Sound → Hardware and Printers.
Download your image file:
Start Etcher
Select the compressed image:
Select the removable drive
You might have to enable unsafe mode if the drive you plugged in has previously been used
in Settings, enable Unsafe mode
Select the removable drive
Select the removable drive
Write image.
click Flash
It might take 20 minutes to write a 20GB (uncompressed) image.
Make coffee.
When the image is finished writing, close etcher and use the Safely Eject Thing dialog in the system tray.
right click
select device
Unplug your drive from the computer, remove the msata drive drive from the USB caddy and then install into your embedded device