This is an old revision of the document!
As of now, Aireplay-ng only supports injection on Prism2, PrismGT, Atheros, Broadcom (with the b43 driver), Intel IWL, RTL8180, RTL8187, Ralink, ACX1xx and Zydas. Injection on Hermes, Aironet and Marvell is not supported because of firmware and/or driver limitations.
There are two families of drivers - ieee80211 and mac80211. Basically, mac80211 has largely replaced ieee80211. See this write-up for more detail. Where the mac80211 version of the driver is stable and supports injection, that should be your first choice. Keeping in mind that mac80211 is only well supported starting in about 2.6.25 and up kernels. However, in some cases, only legacy ieee80211 drivers exist for injection.
Nearly all non-mac80211 drivers that can support injection need to be patched to support injection in Monitor mode. On the other hand, the mac80211 versions of the drivers generally only need the mac80211 core itself patched to support the fragmentation attack. Other attacks using mac80211 drivers typically work without patching.
Remember you cannot use both ieee80211 and mac80211 versions of the same driver at the same time. You must decide to use one or the other, not both. If you try loading both, one will fail. So you must consciously decide which one you wish to use and blacklist the other one if you have both on your system.
You will need the following to compile drivers:
Note: if you're using drivers provided by your distribution, they are NOT patched.
General information about patching drivers plus troubleshooting tips can be found in the How To Patch Drivers Tutorial.
The following are detailed instructions for installing/patching the ieee80211 versions of the drivers:
For fragmentation support, all mac80211 drivers require the mac80211 core to be patched:
The mac80211 link above also contains information regarding which mac80211 drivers work with the aircrack-ng suite.
In addition, the following mac80211 drivers require extra patches to enable or improve monitoring or injection support (purpose of the patch is in parentheses):
Note: For other drivers, simply follow the standard installing procedure for your distribution.
As mentioned previously, the mac80211 drivers quite often support injection out of the box in recent kernels. The mac80211 drivers are improving very rapidly. Sometimes you want to try the latest mac80211 driver without recompiling your entire kernel. This is where Compat-Wireless comes in. You can now download a package which lets you compile and install the latest advances on the Linux wireless subsystem and get some of the latest drivers without having to recompile your entire kernel. This package adds mac80211, mac80211 drivers, and any new FullMAC driver which has had fairly recent updates.
For full details see the Aircrack-ng Compat-Wireless documentation.
Windows is NOT supported.
This troubleshooting information applies to linux only. The individual driver pages may have additional troubleshooting information specific to that driver. This troubleshooting information provides general information which applies to all drivers.
You will need to do a bit of homework first prior to following the troubleshooting tips below. Be sure you know the chipset in your wireless device. Follow this tutorial Tutorial: Is My Wireless Card Compatible? to determine the chipset if you don't already know it. Based on the chipset, determine the proper driver and in turn the kernel modules for it. To do this, you may have to search the internet, the forum and the distribution support.
The first critical step is to ensure that your wireless device is recognized by your system. There are a variety of methods to verify that your system did this successfully. Here are some methods:
Needless to say, if your wireless device is not detected by your system, you will have to investigate and correct the problem.
Start by running “modprobe <kernel module name>”.
Run the “iwconfig” command and look for wireless devices. Based on the driver, look for an appropriately named interface such as ath0, rausb0, etc. The presence indicates that at least the driver is loaded. The absence likely means it did not. This at least gives you a starting point on the problem solving.
A common problem is that your system has both ieee80211 and mac80211 versions of the drivers. Having wmaster0 typically indicates you are using the new mac80211 drivers. Having wifi0 or eth0 typically means you are using the older (legacy) ieee80211 drivers. Having both wmaster0 and wifi0/eth0 (as well as weird interface names like wlan0_rename) might indicate a udev problem. Based on what which ones you really want, you may have to blacklist or move one or more drivers.
Run the “dmesg” command and look for errors relating to your wireless device. At a minimum there should be some messages relating to your device loading and the module initializing it. If there are no messages or errors, you will have to investigate and correct the problem.
See the next entry of a problem commonly seen: “unknown symbol”.
When loading the driver kernel module you get a “unknown symbol” error message for one more field names. Sometimes you will see this in the dmesg output as well. This is caused by module you are loading not being matching the kernel version you are running.
First, determine which kernel you are running with “uname -r”. Then use your package manager to determine if you have kernels, kernel headers or kernel development packages that are older.
If you use the RPM package manager then “rpm -qa | grep kernel”. So if you get something like:
kernel-headers-184.108.40.206-64.fc8 kernel-220.127.116.11-64.fc8 kernel-devel-18.104.22.168-64.fc8 kernel-headers-22.214.171.124-15.fc8 kernel-126.96.36.199-15.fc8 kernel-devel-188.8.131.52-15.fc8
In the example above, there are kernel headers and a kernel development package that match the kernel we are running. If you are missing them, the use yum or equivalent on your distribution to install them such as:
yum -y install kernel-headers yum -y install kernel-devel
Lets assume that “uname -r” returned “184.108.40.206-64.fc8” then all the 220.127.116.11-15 ones are old and need to be removed. So you remove all the old ones:
rpm -e 18.104.22.168-64.fc8 rpm -e kernel-22.214.171.124-15.fc8 rpm -e kernel-devel-126.96.36.199-15.fc8
Also change to “/lib/modules” and do a directory listing and remove any directory referring to old kernel versions.
Once you are finished, you can do ““rpm -qa | grep kernel” and confirm everything looks good. At this point, recompile your wireless drivers and reboot the system.
Run the “lsmod” command can be used to see the loaded modules. Confirm that the kernel module for your wireless device is actually loaded. If it is not loaded, you will have to investigate and correct the problem.
Sometimes other modules conflict with the one you are trying to run. See blacklisting below. Additionally, conflicting modules can be moved out of the module tree. If you do this, run “depmod -ae” afterwards.
Run “modinfo <kernel module name>”. This will confirm the module is actually in the modules tree. As well, confirm it is the correct version. Do a “ls -l <file location per modinfo>” and confirm the date matches when you compiled it. It is not uncommon that you are not running the correct module version.
A common problem on newer kernels is that the new mac80211 version of the driver gets loaded instead of the older legacy driver, or vice versa. If that is the case, then you need to blacklist the wrong modules by editing /etc/modprobe.d/blacklist. First, determine the broken module names and add them to the blacklist file as “blacklist <module name>”.
Specifically for madwifi-ng, do a locate or find for ath5k.ko. If ath5k.ko exists then add “blacklist ath5k” to /etc/modprobe.d/blacklist and reboot. Same for the other way around: if you want to load ath5k, but madwifi-ng gets loaded instead, add “blacklist ath_pci” to /etc/modprobe.d/blacklist.
Although it is not very “scientific”, sometimes simply unloading then reloading the driver will get it working. This is done with the rmmod and modprobe (or simply modprobe -r and then modprobe) commands.
For b43 and b43legacy, it might also be necessary to reload the underlying SSB module. Similarly, rt2x00 and p54 might need reloading of the common modules (p54common, rt2x00lib, rt2x00usb, rt2x00pci). Sometimes (especially with mac80211 drivers), reloading the stack (for example, modules “cfg80211” and “mac80211”) might do the trick. Also another trick is to do modprobe –show-depends <driver>.
For USB devices, the trick to reloading the driver is to make sure all of its related interfaces are down (usually wlan0, mon0, etc if you only have one USB device). Then you modprobe -r via the driver it is using and reload those drivers again via modprobe.
For PCMCIA devices, it is recommended that you have pcmcia-cs package installed as it has a handy utility known as pccardctl. To eject the device virtually, make sure that the interfaces are down following similar guide to USB devices. Once they are down, use pccardctl eject to virtually eject the card/s. Remove all the modules related to the card (hint: if you weren't familiar with the drivers that were used, before you eject the card/s make sure that you do lspci -k as this will list all the devices connected via PCI bus and their related drivers). Once you have removed it, do pccardctl insert and the driver should be loaded automatically. If not load them manually via modprobe.
For PCI devices, there is no real shortcut as the device will remain permanently used by the driver. You will need to reboot for the new driver to take effect.
There is a new wireless stack starting in the mainline kernel since 2.6.22 called mac80211. As newer versions of the kernel get released more and more wireless devices are being supported by it. It has the huge advantage of being included in the kernel itself. The mac80211 stack has features such as software MAC (media access controller), hostapd, WEP, WPA, WME, a “link-layer bridging module,” and a QoS (quality of service) implementation. Of specific interest to aircrack-ng is native monitor mode and injection support.
The legacy drivers use the ieee80211 or net80211 stacks. And quite often there is one stack per wireless device. Depending on the driver, it does not provide native monitor mode or injection support.
So with this as background, here is troubleshooting information for problems that arise when both stacks are installed on a system. There are four classes of problems:
You can tell if you are running the new mac80211 stack based on the kernel version or you likely get an error message similar to:
airmon-ng start wlan0
Interface Chipset Driver wlan0 iwl4965 - [phy0]/usr/sbin/airmon-ng: line 338: /sys/class/ieee80211/phy0/add_iface: Permission denied mon0: unknown interface: No matching device found (monitor mode enabled on mon0)
or in aircrack-ng v1.0-rc1 and newer:
airmon-ng start wlan0
Interface Chipset Driver wlan0 iwl4965 - [phy0] ERROR: Neither the sysfs interface links nor the iw command is available. Please download and install iw from http://dl.aircrack-ng.org/iw.tar.bz2
Notice the reference to “phy0” and “mon0”. Read the page mac80211 for a fix for this error. if the error doesn't show up, then the correct output of airmon-ng is like this:
airmon-ng start wlan0
Interface Chipset Driver wlan0 iwl4965 - [phy0] (monitor mode enabled on mon0)
Another indicator of the mac80211 driver being loaded is if the output from iwconfig includes:
wmaster0 no wireless extensions.
Notice the reference to “wmaster0”.
Perhaps the most consistent way of determining the stack type of your drivers is running the command “lsmod | grep mac80211.” If the output includes a line like this:
mac80211 229108 4 rt2x00usb,b43,rt2x00lib,zd1211rw
then the modules at the end of the line are mac80211 drivers.
If the new mac80211 driver is not working to your satisfaction then you will have to blacklist it and then use the ieee80211 legacy version. The wiki driver section on this page has links to the various drivers.
It is also possible that the new driver is not working because your version of aircrack-ng is too old. Updating to at least 1.0-rc1 often fixes such problems.
If you are using a legacy driver, and want to switch to the mac80211 driver, then you need to blacklist the old driver, and enable the new one. If the names of the old and new in-kernel drivers match (for example, with zd1211rw, which is softmac in 2.6.24 and before, but mac80211 in 2.6.25), then you need to upgrade your wireless subsystem (either by updating the kernel or using compat-wireless-2.6).
If you have conflicts due to running both drivers, then decide which one you want and blacklist the other one.
When using an USB device and you get a message similar to this from dmesg:
rt73: Firmware loading error rt73: Failed to load Firmware. rt73: probe of 1-7:1.0 failed with error -71
Note: Although the example shows RT73, this applies to any USB driver.
Here are a few things to check:
Some laptops have a bios setting and/or a physical switch to enable/disable internal wireless cards. Make sure that these are are all “turned on” so that your wireless card is operational.