On Linux

On Linux, installing the WAN Emulation driver depends on the system characteristics. The following process must be used as a general frame only.

Prerequisites

Before installing the driver on Linux, it is necessary to have installed:

Neotys Design Studio installed beforehand, as documented in Install the Controller and Install a Load Generator Agent.
Linux kernel 2.6 and above
Tools like gcc and make installed
Linux kernel sources

A common way to install and prepare kernel sources is to execute the following commands:

yum install -y kernel-devel-`uname -r`

cd /usr/src/kernels/`uname -r`

make oldconfig

make prepare

make scripts

To install the WAN Emulation driver on a Linux system

A common way to compile the ipfw module on most common Linux distributions is:

cd <neoload>/tools/ipfw/linux

unzip ipfw-linux-src.zip -d ipfw-linux-src

cd ipfw-linux-src

make KERNELPATH=/lib/modules/`uname -r`/build

Once the compilation is successful, the ipfw binaries need be placed in a specific Neotys Design Studio directory with:
```
cd <neoload>/tools/ipfw/linux
```
```
cp ipfw-linux-src/ipfw/ipfw .
```
```
chmod +x ipfw
```
```
cp ipfw-linux-src/dummynet2/ipfw_mod.ko .
```
Before launching the NeoLoad Agent, the ipfw module needs be loaded into the system with:
```
cd <neoload>/tools/ipfw/linux
```
```
insmod ipfw_mod.ko
```
Be careful with this command as it may need root privileges to be executed successfully. If it is the case, see step 5.
Then you can check that the module is correctly running with:
```
./ipfw list
```
The result should be something like: 65535 allow ip from any to any

Be careful with this command as it may need root privileges to be executed successfully. If it is the case, see step 5.
The Controller or the Load Generator Agent must execute the ipfw command. You have to ensure that the account running Neotys Design Studio has sufficient privileges to execute it.
This can be achieved by giving the account running Neotys Design Studio a sudo access without a password prompt to the program with:
- Using the root account, launch the command visudo
- Add the following line:
```
<user>    ALL=(ALL)    NOPASSWD: <neoload>/tools/ipfw/linux/ipfw, /sbin/insmod, /sbin/rmmod
```
  Make sure that there is a line like Defaults:<user> !requiretty
  
  Replace <user> with the user launching Neotys Design Studio.
  
  Replace <neoload> with the Neotys Design Studio installation folder.
- Then edit the file: <neoload>/conf/agent.properties:
  In section: [Network]:
  - Set the location of the ipfw binary in the ipfw.dir key:
  ipfw.dir=tools/ipfw/linux
  - Add the following lines:
  ipfw.prefix=sudo
  
  ipfw.mod.load=sudo insmod ipfw_mod.ko
  
  ipfw.mod.unload=sudo rmmod ipfw_mod.ko
Restart Neotys Design Studio.

Tip: Because installing the WAN Emulation driver on a Linux system may be troublesome, the Neotys Cloud services may be used for on-the-spot tests. The Neotys Cloud services offer ready-to-use Linux machines with the WAN Emulation function already implemented. For more information, see Test from the Cloud.