This is our old Q&A Site. Please post any new questions and answers at

Hi all, I split a pcap in 3 small pcap files and then I merged back altogether. I was supposing that the merged one is equal to initial file, but I found many differences. Could someone explain to me why?


editcap test_initial.pcap test_A.pcap 1-300
tshark -nr test_initial.pcap -R "frame.number==301" -w test_B.pcap
editcap test_initial.pcap test_C.pcap 302-999999999

mergecap -w test_merged.pcap \
            test_A.pcap \
            test_B.pcap \

tshark -nr test_initial.pcap -T pdml > test_initial.xml
tshark -nr test_merged.pcap -T pdml > test_merged.xml
diff test_initial.xml test_merged.xml

asked 03 Oct '13, 06:17

Ric79's gravatar image

accept rate: 0%

edited 03 Oct '13, 06:18

Can you post the initial pcap anywhere folks could have a look? What's the capinfos report on the initial and merged pcaps?

(03 Oct '13, 06:23) grahamb ♦

@grahamb You can use a generic test_initial.pcap file...

(03 Oct '13, 23:17) Ric79

editcap will not save the listed packets by default. You need to use the "-r" flag to save frames 1-300 to a new file like this:

editcap -r test_initial.pcap test_A.pcap 1-300
permanent link

answered 03 Oct '13, 07:22

SYN-bit's gravatar image

SYN-bit ♦♦
accept rate: 20%

Thanks.. after adding a "-r" flag to editcap, the process works nicely! Is there a way to use editcap also for extracting just ONE frame?

(03 Oct '13, 23:19) Ric79

Maybe try "editcap -r test_initial.pcap test.pcap 1-1"? :-)

(03 Oct '13, 23:24) Jasper ♦♦

Or just use "1":

$ editcap -r http.cap /tmp/x.pcap 1
Add_Selected: 1
Not inclusive ... 1
$ capinfos -Tc /tmp/x.pcap 
File name   Number of packets
/tmp/x.pcap 1

(04 Oct '13, 00:14) SYN-bit ♦♦

@Jasper ... your solution is nice also for n-th frame, not just for the first one

editcap -r test_initial.pcap test_B.pcap 301-301

(04 Oct '13, 01:58) Ric79
Your answer
toggle preview

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here



Answers and Comments

Markdown Basics

  • *italic* or _italic_
  • **bold** or __bold__
  • link:[text]( "title")
  • image?![alt text](/path/img.jpg "title")
  • numbered list: 1. Foo 2. Bar
  • to add a line break simply add two spaces to where you would like the new line to be.
  • basic HTML tags are also supported

Question tags:


question asked: 03 Oct '13, 06:17

question was seen: 1,887 times

last updated: 04 Oct '13, 01:59

p​o​w​e​r​e​d by O​S​Q​A