How to capture Packet from specific port

Question

Hi Guys,

I want to capture packets from a particular port no. But I am able to capture packets from all the ports. How can I allow only one port?

Answer 1

Hi@akhtar,

Let’s say you want to capture packets for specific port 22, then you can execute the below command by specifying port number 22 as shown below.

$ tcpdump -i eth0 port 22

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
10:37:49.056927 IP 192.168.0.2.ssh > 192.168.0.1.nokia-ann-ch1: Flags [P.], seq 3364204694:3364204890, ack 4193655445, win 20904, length 196