Original subtitles

‫From the previous lectures,

‫we learned the basics of how networks work.

‫We learned that devices on the same network communicate

‫with each other using packets.

‫So regardless of what you do on the network,

‫whether you're watching a video,

‫whether you're logging into a website,

‫sending chat messages, sending emails,

‫regardless of what you're doing,

‫all the data is sent as packets.

‫Now, in the network,

‫devices ensure that these packets go

‫in the right direction using the MAC address

‫so each packet has a source MAC and a destination MAC

‫and it flows from the source to the destination.

‫So in this example, we have the client,

‫it has this MAC,

‫we have the access point which has this MAC

‫and as an example, if this client wanted

‫to send a packet to the router,

‫it will set the destination MAC

‫to the router's MAC address.

‫Therefore, by default,

‫each device only receives data that has the destination MAC

‫as its own MAC address.

‫But if you remember, I said in wireless networks,

‫if you're within range,

‫then you'll be able to capture all of this communication

‫because these packets are literally sent in the air.

‫So we can just capture them

‫even if they do not have our MAC address

‫as the destination MAC.

‫To do this, we need to change the mode

‫of operation of our wireless interface

‫so that it operates in monitor mode.

‫So let me show you what I mean.

‫If I go to my computer here,

‫and run iwconfig this time,

‫so we've seen ifconfig which lists all the interfaces,

‫we can use iwconfig to see the wireless interfaces only.

‫And you can see, we have lan0 right here

‫which is my external wireless adapter.

‫And you can see the mode of this adapter

‫is set to Managed.

‫What this means is basically this is the default mode

‫of all wireless devices

‫and what it means is this device

‫will only capture packets

‫that has the destination MAC

‫as the MAC address of this device.

‫So basically it'll only capture devices

‫that are directed to my Kali machine.

‫But this is not what we want.

‫What we want is to be able to capture all the packets

‫that are within our range,

‫even if they are sent to the router

‫and even if they are set to another device.

‫So to do this, we need to set the mode

‫to Monitor mode instead of Managed mode.

‫So as usual, before you can change the options

‫of your interface, you have to disable it

‫and previously, we've seen we can do that

‫by doing ifconfig, the device name

‫which is lan0 in my case, down.

‫Then we can enable monitor mode.

‫But before we do that,

‫I'm actually going to run a command

‫to kill any process

‫that could interfere with using my interface

‫in monitor mode.

‫So the command that I'm gonna run right now

‫is not mandatory

‫but running it will actually give you better results

‫when you come to running the attacks

‫that you will learn as we go in the course.

‫So this command is gonna be airman-ng check kill.

‫Now you'll notice when you're on this command,

‫it'll actually kill the network manager

‫that usually runs in here.

‫So you'll completely lose your internet connection.

‫But this is no problem

‫because we will only need to be in monitor mode

‫when we are running pre-connection attacks

‫so attacks that do not require us

‫to connect to any network.

‫So we actually do not need internet connection

‫to run any of the attacks that require monitor mode.

‫Now we're gonna enable monitor mode.

‫So we're gonna do iwconfig.

‫Followed by the interface name

‫that we want to enable monitor mode on

‫which is lan0.

‫We're gonna say that I want to change the mode

‫and I want to change that to monitor.

‫So very, very simple command.

‫We're using iwconfig to change the mode.

‫We're giving the name of the interface

‫that we want to change its mode.

‫We're saying I want to change the mode

‫and I want to set it to monitor mode.

‫Now, if I hit Enter, you'll see the command will run

‫with no errors which means the command got executed properly

‫and finally, we'll need to enable the interface,

‫again similar to what we did

‫when we changed the monitor address.

‫So we just have to do ifconfig lan0 up.

‫That's done.

‫Now, if I run iwconfig again,

‫you'll see that the mode is set to Monitor now.

‫So basically this interface now can be used

‫to capture any packet that is within our range,

‫not only the packets that are directed

‫to this computer.

‫That's why in the future you'll see how we can use it

‫to sniff packets, to analyze them

‫and even break into networks.

‫So in the future,

‫if I say use your interface in monitor mode,

‫this is what I mean.

‫You'll basically have to enable monitor mode

‫as shown in here.

‫Now, I've also included a YouTube video

‫in the resources of this lecture

‫to show an alternative method

‫to enable monitor mode

‫just in case you got errors with this method

‫or you tried to follow something

‫that I do in the next lectures

‫and it didn't work.

‫Then you can come back and try the alternative method.

‫But if this worked and if monitor mode

‫is enabled successfully,

‫then you don't need to watch that video,

‫you can just continue with the course.

‫One more thing to keep in mind,

‫not all wireless adapters support monitor mode.

‫So for this to work,

‫you need to make sure

‫that your actual adapter supports monitor mode.

‫There are a number of adapters that support that

‫and I've included another video again in the resources

‫of me talking about wireless adapters,

‫hot to pick the best one

‫and which ones that I recommend and use

‫when I'm testing the security of networks.