01-17-2008
tcpdump question
Hi, I got the following question regarding tcpdump and I would appreciate your help/feedback:
--Scenario
I am instructed to capture the network traffic by getting the tcpdump data/files of our network for every hour.
--Problem
Some of the connections are still open when the capture is done at the end of 30 minutes. How do I link these open connections in different tcpdump files?
--example
Connection A: 192.168.10.1:1686 --> 192.168.10.22:139
connection A starts: 12:25
connection A ends: 12:45
Data capture: 12:00-12:30 (file1), 12:30-1:00 (file2)
Will there be two connections (for connection A) -- one in file1, the other in file2? Will their connection start time be the SAME or DIFFERENT?
Please help!!
Thanks!!
Jay
9 More Discussions You Might Find Interesting
1. Programming
I have two net-card. one is 172.16.24.99(ENG) ,another is 172.16.25.99(ENG-B). Both masks is 255.255.255.0.
I will monitor data on the tcp port 8055 in ENG, How do I set option of tcpdump command (2 Replies)
Discussion started by: chenhao_no1
2 Replies
2. UNIX for Dummies Questions & Answers
does anybody know what the -d -dd and -ddd options are used for ?
thanks (2 Replies)
Discussion started by: ant04
2 Replies
3. Cybersecurity
i would like to know about tcpdump
i would like to use tcpdump to get information about these
- Date
- time
- source hostname
- source mac address
- source ip address
- destination ip address
- see outbound only
then i use command like this
tcpdump -i le0 -n -q -tttt -e src net... (0 Replies)
Discussion started by: chamnanpol
0 Replies
4. IP Networking
i would like to know about tcpdump
i would like to use tcpdump to get information about these
- Date
- time
- source hostname
- source mac address
- source ip address
- destination ip address
- see outbound only
then i use command like this
tcpdump -i le0 -n -q -tttt -e src net... (2 Replies)
Discussion started by: chamnanpol
2 Replies
5. UNIX for Dummies Questions & Answers
Hello everyone!
I installed OpenWRT on a WRT54G-TM (linux 2.4). No problem so far!. I also installed tcpdump on the box.
I set the adapter in monitor mode.
wlc monitor 1
It created the prism0 interface. Tcpdumpíng is also possible using this interface.
root@cmWRT:/tmp# tcpdump -i... (1 Reply)
Discussion started by: aztroboy
1 Replies
6. IP Networking
Please look at the third line that the windows size is 257, but in the fourth line it sends 992 bytes. Can anyone tell me why?
Thanks in advance!!!
http://life.chinaunix.net/bbsfile/month_1108/1108241440ce458925d2bb6d73.png (3 Replies)
Discussion started by: cateran
3 Replies
7. IP Networking
Hi,
I am trying to capture manually crafted IP packets, created using Scapy, to a pcap file that can later be replayed using tcpreplay.
When using wireshark, I can successfully capture these packets and view them in wireshark.
However, when using tcpdump, these packets are then shown in... (2 Replies)
Discussion started by: yotamhc
2 Replies
8. Debian
Hi.
Need Help with TcpDump
Trying to sniff associatio-request with tcpdump but when i run this tcpdump -i eth0 wlan subtype assoc-req i get this error
can anyone help me with this error ? Thanks alot !!:) (1 Reply)
Discussion started by: SoulZB
1 Replies
9. IP Networking
I've recently started learning to use TCPdump, and I find it pretty interesting. There's one thing I don't understand. When I tell it to capture packets on, say, the WiFi interface en1, it often captures packets sent or received by other hosts on the network. How can it do this? My... (3 Replies)
Discussion started by: Ultrix
3 Replies
LEARN ABOUT FREEBSD
ipresend
IPRESEND(1) General Commands Manual IPRESEND(1)
NAME
ipresend - resend IP packets out to network
SYNOPSIS
ipresend [ -EHPRSTX ] [ -d <device> ] [ -g <gateway> ] [ -m <MTU> ] [ -r <filename> ]
DESCRIPTION
ipresend was designed to allow packets to be resent, once captured, back out onto the network for use in testing. ipresend supports a num-
ber of different file formats as input, including saved snoop/tcpdump binary data.
OPTIONS
-d <interface>
Set the interface name to be the name supplied. This is useful with the -P, -S, -T and -E options, where it is not otherwise possi-
ble to associate a packet with an interface. Normal "text packets" can override this setting.
-g <gateway>
Specify the hostname of the gateway through which to route packets. This is required whenever the destination host isn't directly
attached to the same network as the host from which you're sending.
-m <MTU>
Specify the MTU to be used when sending out packets. This option allows you to set a fake MTU, allowing the simulation of network
interfaces with small MTU's without setting them so.
-r <filename>
Specify the filename from which to take input. Default is stdin.
-E The input file is to be text output from etherfind. The text formats which are currently supported are those which result from the
following etherfind option combinations:
etherfind -n
etherfind -n -t
-H The input file is to be hex digits, representing the binary makeup of the packet. No length correction is made, if an incorrect
length is put in the IP header.
-P The input file specified by -i is a binary file produced using libpcap (i.e., tcpdump version 3). Packets are read from this file
as being input (for rule purposes).
-R When sending packets out, send them out "raw" (the way they came in). The only real significance here is that it will expect the
link layer (i.e. ethernet) headers to be prepended to the IP packet being output.
-S The input file is to be in "snoop" format (see RFC 1761). Packets are read from this file and used as input from any interface.
This is perhaps the most useful input type, currently.
-T The input file is to be text output from tcpdump. The text formats which are currently supported are those which result from the
following tcpdump option combinations:
tcpdump -n
tcpdump -nq
tcpdump -nqt
tcpdump -nqtt
tcpdump -nqte
-X The input file is composed of text descriptions of IP packets.
SEE ALSO
snoop(1m), tcpdump(8), etherfind(8c), ipftest(1), ipresend(1), iptest(1), bpf(4), dlpi(7p)
DIAGNOSTICS
Needs to be run as root.
BUGS
Not all of the input formats are sufficiently capable of introducing a wide enough variety of packets for them to be all useful in testing.
If you find any, please send email to me at darrenr@pobox.com
IPRESEND(1)