I have a pcap captured with Wireshark. Is there any function in Wireshark that will strip Ethernet layer from the result? Or any command line tool to do it?
I searched a bit more about pcap editors, and I found that this works:
$ bittwiste -I a.pcap -O b.pcap -M 12 -D 1-14
-M 12 sets link type to RAW
-D 1-14 deletes bytes 1-14 in link data layer (Etherenet frame is 14 bytes long)
When I open up result in Wireshark I see "Raw packet data (No link information available)" and IP frame below. So this is what I needed.
Related
Attempting to capture traffic but I don't know the write syntax to filter the output to a readable pcap file.
I need to use the syntax
tcpdump -r file.pcap
and to filter eth0 icmp traffic
tcpdump -i eth0 icmp -c 10 > file.pcap
is there a way to do this in one line of command?
Yes, but, if you're writing a pcap file rather than a text file, it doesn't involve the > character.
By default, tcpdump captures traffic from an interface, or reads a capture file, and writes out a human-readable dissection of the packets to the standard output.
You need the -w flag to write out a pcap file, so, in your case, the command is
tcpdump -r file.pcap -w file.pcap ICMP
Your command
tcpdump -i eth0 icmp -c 10 > file.pcap
wouldn't write out a pcap file, it writes out text such as
16:30:59.808885 IP 192.168.1.5 > example.com: ICMP echo request, id 40541, seq 0, length 64
16:30:59.841404 IP example.com > 192.168.1.5: ICMP echo reply, id 40541, seq 0, length 64
If you wanted to write the ICMP traffic to a pcap file, you would do
tcpdump -i eth0 icmp -c 10 -w file.pcap
I would like to know that is there any option in Wireshark to capture packets in the streaming network dynamically. Since I need to capture packets with out doing the export each time and packets capture automatically in a CSV file without exporting it periodically. Thanks.
You should be able to use tshark to achieve this. For example, suppose you want to capture the frame number and source and destination IP addresses of each packet (to keep the example simple), you could use:
tshark -i foo -T fields -E separator=, -E quote=d -E header=y -Y ip -e frame.number -e ip.src -i ip.dst > output.csv
You can specify as many fields as you want using the -e option
I want filter first 100 packets inside a pcap file and show the result on stdout. for filtering first 100 packet I used below command:
editcap -r test.pcap output.pcap 1-100
for showing result and filtering packet for the further purpose I want to used tcpdump.
tcpdump -tttt tcp and host ip 192.168.1.1 -r inputfile.pcap
i want to redirect output of editcap to tcpdump, like this:
editcap -r test.pcap - | tcpdump -tttt tcp and host ip 192.168.1.1 -r -
but in this command I couldnt filter first 100 packets. Is it possible to do so??
If not is it possible to rediredt output of editcap to RAM and then the tcpdump read from RAM ??
thanks in advanced.
P.S by the way, I don't want to use the below command, because this command read the all Packet inside the file. I need the command read some packets inside he pcap file and shows then was finished the job.
tshark -r ~/test1.pcap -R "frame.number<20 and frame.number>10"
but in this command I couldnt filter first 100 packets
I.e., you don't see any packets?
Try doing
editcap -F pcap -r test.pcap - 1-100 | tcpdump -tttt tcp and host ip 192.168.1.1 -r -
as editcap might be writing out a pcap-ng file and there is a bug in some versions of libpcap when reading pcap-ng files that causes filtering in tcpdump not to work.
I want to capture messages of Diameter protocol (over SCTP) by tshark on the screen, expanded.
First, I couldn't find what to write after switch '-f' to filter only diameter messages, but then I found the switch '-R' which accepted 'diameter'.
So, currently my command seems like:
tshark -i el0 -R diameter -V
This is all fine, at least, until the packets are small enough..
However, for bigger packets, I get the error [Unreassembled Packet: DIAMETER]
[Expert Info (Warn/Reassemble): Unreassembled Packet (Exception occurred)]
[Message: Unreassembled Packet (Exception occurred)],
and the packets are indeed not reassembled in the output.
I was googling for solution, and found that the below modification might do the defragmentation:
tshark -i el0 -R diameter -V -o ip.defragment:TRUE
But it just doesn't help.
Any simple solution for this problem? (It is also ok to process the defragmentation afterwards somehow..)
Finally I have found it!
In wireshark there is a checkbox for several protocol related options, in particular, for diameter defragmentation you need to mark the checkbox
Reassemble fragmented SCTP user messages
to get the long diameter messages properly displayed.
Each of these protocol options has its own tshark correspondent parameter, here you have to use -o sctp.reassembly:TRUE.
(For general, look for the file preferences belonging to wireshark.)
So, what method finally worked is
First capture all (sctp) messages regularly:
tshark -i EL0 -f sctp -w raw_capture.pcap
Then, if it is done, process the file by a further tshark command:
tshark -r raw_capture.pcap -R diameter -o sctp.reassembly:TRUE -V
I'm analyzing VoIP calls on my network
For now i'm using a generated .pcap file, but later i'll be listening for this at real time.
I'm using tshark, and i can filter some important data pretty easily from the .pcap (like "source ip address and port", "destination ip addr and Port", payload pckt lost, Max Delta(ms),Max Jitter(ms),Mean Jitter(ms)) with
tshark -r myfile -q -z rtp,streams
What i want to know is: how can i get the sip addrs of a call? (client and server)
I can retrieve some sip addrs (only client) by filtering all sip INVITE like this:
tshark -r myFile -R "sip.Request-Line contains INVITE"
But i can't get the address of the server.
To clarify a bit, my idea was to get this "statistic" in tshark, like wireshark gives me when i access "Telephony>VoIP Calls" (the same way that tshark -r myfile -q -z rtp,streamsreturns me statistics just like wireshark's Telephony>RTP>Show All Streams), is there a way to do this? If not with "statistics" (-z) how can i create a filter (-R) to do something similar of the "VoIPCall" function of wireshark
I'm using tshark as i want to work with this data, and not just analyze it on my screen
Thanks
try:
tshark -r myFile -R "sip.CSeq.method eq INVITE"
That will filter for the request sent from the client and the corresponding reply from the server.
I was in a similar situation and ended up going through tshark man pages.
Command: tshark -r input_file.pcap -q -z sip,stat
Explanation:
-r <infile> : Read packet data from infile
-q : When reading a capture file, don't print packet information; this is useful if you're using a -z option to calculate statistics and don't want the packet information printed, just the statistics.
-z <statistics> : Get TShark to collect various types of statistics and display the result after finishing reading the capture file.
You can additionally add filters to the filtering as well, so for example you want to summarize all packets which had only SIP 480 Status Code, you can do so by:
tshark -r input_file.pcap -q -z sip,stat,sip.Status-Code==480
-z sip,stat[,filter] : This option will activate a counter for SIP messages. You will get the number of occurrences of each SIP Method and of each SIP Status-Code
In case you want multiple filters, you can add them one by one
tshark -r input_file.pcap -q -z sip,stat,sip.Status-Code==480 -z sip,stat,sip.Status-Code==500
If you want to summarize by sip address, you can filter by that:
tshark -r input_file.pcap -q -z sip,stat,sip.to.host==sip-to-host.com
Refer:
TShark Man Page: https://www.wireshark.org/docs/man-pages/tshark.html
SIP Filters: https://www.wireshark.org/docs/dfref/s/sip.html