I want to sniff wifi packets with wireshark but monitor mode seems to fail. I'm using backtrack 5 and an alpha AWUS036H wifi usb card, i try to sniff my own box without encryption.
Here is what i'm doing to activate monitor mode :
root#root:~# airmon-ng start wlan0
wich seems to be working :
root#root:~# iwconfig mon0
mon0 IEEE 802.11bg Mode:Monitor Tx-Power=20 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Power Management:on
However when i start capturing on mon0 in wireshark i'm only getting broadcast packets.
In capture options the "capture packets in monitor mode" option is grayed out.
I do not understand what's going on. Any Ideas ?
What channel number is your mon0 interface set to?
Related
I know I can send 802.11 custom packets with wifi_send_pkt_freedom, and I'am using it without any problem.
But what about receiving?. Yes, I can enable promiscuos mode, and filter by MAC address. Doing that is perfect for sniffing, but not for communication, because the ESP8266 won't ACK the packets and if I'am not sniffing and my ESP is the only receiver, it will make the transmitter to repeat many times the packet. Yes, I can send it like broadcast or multicast to avoid waiting for the ACK, but I'll missing the ACK/re-send functionality. In short I would like to put the ESP Wifi interface in monitor mode (which is not promiscuos mode)
And yes, I can use ESPNOW, but for my application it wont suit very well my needs.
Thanks!
Román
When I use Wireshark to capture traffics with my wlan card with monitor mode already set, it only displays 802.11 frames. However, if I use Wireshark with managed mode wlan(promiscuous mode), it certainly displays 802.3 frames.
I searched for some related information and found out that 'network bridging' allows devices to convert 802.11 wireless packets to 802.3 packets. In case of packet capturing, pcap allows conversion.
(link: How to real time convert wireless packet(802.11) to Ethernet packet(802.3) in windows?)
So, Why is 802.11 to 802.3 frame conversion impossible when using monitor mode(not associated to the wireless network)?
Below are pictures of the situation. Thank you in advance.
Promiscuous mode packet capture
Monitor mode packet capture
For one thing, not all 802.11 packets have Ethernet equivalents; only data packets do. In monitor mode, in addition to data packets, control and management packets can be captured - you're seeing those types of packets in your monitor-mode capture.
For another thing, when capturing in monitor mode on a "protected" network (WEP, WPA), data packets are encrypted (to protect them from being sniffed), and can't be converted to Ethernet packets until they're decrypted. Under some circumstances, Wireshark can decrypt them, but Wireshark doesn't do any conversion from 802.11 to 802.3 in any circumstances - when not capturing in monitor mode, the 802.11 adapter converts data packets to 802.3 packets after decrypting them, and doesn't show non-data packets to the host.
After setting up promiscuous mode on my wlan card, I started capturing packets with wireshark. But only broadcast packets or packets destined to my localhost were captured. I cannot find the reason why.
Also, after changing to monitor mode, captured packets all had 802.11 headers unlike promiscuous mode where Ethernet frames were captured. I know devices communicate with 802.11 protocols when wireless. But how is it possible that packets captured in wireshark is displayed in Ethernet frames? (when not in monitor mode)
I want to observe streams between the original screen mirrored from and the target screen mirrored to to check something like frame loss, thus I'm thinking to sniff packets between sender and receiver.
Is there any plugins for Wireshark which enables me to do that..?
What you have to do is to route the network traffic through some network node that you can sniff on. Like your laptop.
I would connect the laptop to the Internet through ethernet and make a wifi hotspot on it. Then tell chromecast to connect to your hotspot. Now you're in the middle between chromecast and the Internet. Wireshark should be able to capture the traffic without any specific plugins.
Make sure you've enabled routing between ethernet and wifi hotspot.
I want to analyze networks traffic but not by connecting it Just
switch on wifi and sniff the packets (IEEE 802.11 Frames)
in promiscuous mode
I have tried libpcap but it may be internally changing datalinktype as i am giving wifi interface in
descr=pcap_open_live("en1", MAXBYTES2CAPTURE, 1, 512, errbuf);
(as we know mac OS x have en1 as wifi interface )
now when i do this
printf("%s", pcap_datalink_val_to_name( pcap_datalink(descr)));
It gives me result "ethernet"
I have tried to capture packets using wireshark without connecting to my wifi network and it worked!!
I was able to capture Beacon , Acknowledgement and Authentication frames without connecting to my wifi network.
now:
do I have to make a network card driver for that or libpcap can do that ?if yes how?
Is wireshark making some kind of driver for that? if yes please help me to locate that in it's source code.
I have tried Apple's CFNetwork but it too can't capture without connecting to the network.
It will be very helpful if i get some suggestion on some user space code as kernel level coding is a little tuff :(
I am coding on MacOS 10.7 in xCode 4.5.1
Update:
I am already doing this:
descr=pcap_create("e1", errbuf);
pcap_set_rfmon(descr, 0);
pcap_set_promisc(descr, 0);
pcap_activate(descr);
descr=pcap_open_live("en1", 2048, 1, 512, errbuf);
And yes there is a little monitor icon at the wifi and I can sniff the
packets but only when I connect to the network, I want to do the same
when I am not connected to wifi like capturing Beacon and
Acknowledgment Frames means packets through which our network card detects available wifi network
If you're running on Snow Leopard or later (which you are, as you're running Lion), you should use the new pcap_create()/pcap_activate() APIs, and turn on monitor mode by calling pcap_set_rfmon() between the pcap_create() and pcap_activate() calls.
That's what Wireshark 1.6.0 and later do if you check the monitor mode checkbox, and what tcpdump 1.0.0 and later, and TShark and dumpcap in Wireshark 1.6.0 and later, do if you specify the -I command-line flag.
By default, Wi-Fi interfaces on many OSes, including but not limited to OS X, supply Ethernet headers, not 802.11 headers, which is why pcap_datalink_val_to_name(pcap_datalink(descr)) is reporting Ethernet headers. On Linux and OS X, you have to go into monitor mode to get 802.11 headers; on *BSD, you can get 802.11 headers without going into monitor mode.
You do not need your own driver to go into monitor mode on OS X; Wireshark does not supply its own drivers.