How can I capture 802.11 packets?

[maria1981]

Hi all!

I need your help please. I have established an ad-hoc IEEE 802.11b (11Mbps) WLAN using BELKIN Wireless Desktop Network Cards and I need to use a software, probably a network analyzer (Ethereal??) to capture 802.11 packets and get information about their 802.11 header, receiver and sender, how many packets were lost, arrival times and other relevant information.

Can anyone help me? I have used Ethereal but instead of an 802.11 header it sees an Ethernet header. Ethereal can see my wirelss card, so is there anything that I should know?

Thank you!

 

[Worked4me]

No disrespect intended but can you explain what you need
to accomplish by analysing the TCP, and packet structure of
computers in Ad-hoc mode.

Why I ask is that unless you run a secret clearance network
ie(Government) or are contractors for the Government than
Analysinging packets to determine senders and receivers is usually only used when there is a hacker inside that you need to
isolate which is probably not the case.

If this is for a campus because with today's technology you can
transmit data in Ad-hoc mode and bypass the college campus security geeks who analyis what and were you send information from inside a classroom then you should use a different method. Just to through another wrench in the works if they are running
Windows XP Pro and have Remote desktop Connection setup with a weak password the sender info in the packet won't match the actual sender it will match the comprimised boxes info on thier NIC.

 

[maria1981]

I have set up an experiment in my campus. The computers exchange UDP packets (I do not want to use TCP). What I need to check is when they exchange these UDP over wireless packets how many of them are lost due to collisions and then do some other measurements about the latency or the deviation between the arrival times of the packets or the order the packets on the receiver.

I used an ad-hoc network, as I am not connected to the Internet, so no security concerns, and because of reasons of simplicity. So, nothing government-related, I am just doing a project. I know the senders and the receivers, because I only have four PCs and I am the one who says who will transim to whom. So I do not want to analyze senders and receivers, I just want to take some information for the exchanged UDP packets. And I want to see the IP addresses on these packets.

That is why I used Ethereal , because for the Ethernet it works fine and gives all the information I need on the packets. Now I need to do the same with 802.11.

 

[Worked4me]

I know Ethereal is a well known packet sniffer but you may want
to try a few of the other Wireless Packet sniffer's to see if the
meet your needs. I don't sniff wireless packets so I can't recommend any specific program.
Analyzer looks like a promising sniffer
http://analyzer.polito.it/30alpha/

This one also seems pretty good and is on a trial basis
http://www.javvin.com/packet.html

You can also try Sniff-em
http://www.sniff-em.com/download.shtml

Good Luck.

 

[charu]

hi maria...

could you help me on the basic of programing for the ad-hoc IEEE 802.11b? i have serached everywhere on the the net and i'm just not able to find any material on this. plz help!!!

Hi all!

I need your help please. I have established an ad-hoc IEEE 802.11b (11Mbps) WLAN using BELKIN Wireless Desktop Network Cards and I need to use a software, probably a network analyzer (Ethereal??) to capture 802.11 packets and get information about their 802.11 header, receiver and sender, how many packets were lost, arrival times and other relevant information.

Can anyone help me? I have used Ethereal but instead of an 802.11 header it sees an Ethernet header. Ethereal can see my wirelss card, so is there anything that I should know?

Thank you!

 

[maria1981]

Hi charu

What do you mean by saying ad-hoc programming? Routing techniques? The only thing I have done is to set up easily a network by just adding the BELKIN network cards, nothing else. I am not connected to the internet or other network.
I would be glad to help you if you could be more specific....