Important note to remember:
a. capture it in full length, using the -s 0 options
b. save it in a file, better to make the extension as .pcap so wireshark can associate directly
1.Identify which interface you want to listen to
[root@freelinux tmp]# ifconfig
eth0 Link encap:Ethernet HWaddr 08:00:27:72:24:E6
inet addr:10.0.2.15 Bcast:10.0.2.255 Mask:255.255.255.0
inet6 addr: fe80::a00:27ff:fe72:24e6/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:942 errors:0 dropped:0 overruns:0 frame:0
TX packets:612 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:78095 (76.2 KiB) TX bytes:198882 (194.2 KiB)
Interrupt:10 Base address:0xd020
2. Run “tcpdump” command with the following options. For instance, you want to monitor the DNS packets.Run:
tcpdump -ni eth0 -Xvvv -w freelinux.pcap -s 0 port 53
[root@freelinux tmp]# tcpdump -ni eth0 -Xvvv -w freelinux.pcap -s 0 port 53
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
2657 packets captured
2938 packets received by filter
0 packets dropped by kernel
# ls -l /tmp -rw-r--r-- 1 root wheel 1386926 Sep 24 14:39 freelinux.pcap
-s 0 –> capture byte to its maximum (65535) or it’s full lenght
-ni –> listen on which interface. Then -n option is used so not to convert host addresses to names.
-w –> create the file
port –> to indicate the port number, e.g. 53 which pertains to dns
-X –> Print each packet (minus its link level header) in hex and ASCII
-vvv –> Even more verbose output
[root@freelinux tmp]# tcpdump -ni eth0 -Xvvv -w freelinux.pcap -s 0 portrange 67-68
[root@freelinux tmp]# tcpdump -ni eth1 -s0 -w hostlinux.pcap host 18.104.22.168 &
Note: you can do Ctrl+C to terminate the task, or if run in background, kill the process if finished as it will consume some hard disk space and some CPU resources.
3. Now open the wireshark program. It’s a GUI-based program, so viewing is easier and flexible.
I’ll try this. This will be really useful.
Very good blog! Do you have any helpful hints for aspiring
writers? I’m hoping to start my ownn website soon but I’m a ittle lost oon everything.
Would you recommend starting with a free platform like
Wordpress orr go for a paid option? There are so many options out there thst I’m completely confused ..
Any ideas? Kudos!
Hello my friend! I want to say that this articlle is
awesome, nice written and come with almost all significant infos.
I would like to look extra posts like this .
Hi, always i used to check weblog posts here early in the dawn,for the reason that
i likme to find out more and more.