Wireshark-users: Re: [Wireshark-users] file format question
From: Guy Harris <[email protected]>
Date: Mon, 22 Aug 2011 13:28:48 -0700
On Aug 22, 2011, at 1:08 PM, János Löbb wrote:

> [email protected]:~# tcpdump -c1000 net xxx.yy.zz.0/24 > /tmp/tcpdump.pcap

That should be "> /tmp/tcpdump.txt"...

...because tcpdump's default output format is a textual dissection of the packets.

> The file "/Volumes/Home/janos/tcpdump.pcap" isn't a capture file in a format Wireshark understands.

Yup.  Wireshark can't read tcpdump's (or Wireshark's/TShark's) textual dissection(s) of packets as a capture.

> So the question is how should I do the tcpdump on Ubuntu to be able to open it in Wireshark on my Mac ?

With the "-w" flag, to get it to write out the raw packet data in pcap format, rather than writing out the dissected packets as text:

	tcpdump -c1000 -w /tmp/tcpdump.pcap net xxx.yy.zz.0/24