Sometimes our network service won’t behave as per our requirement and in most of the cases the log do not help us to trace out the issue. Here comes the role of tcpdump and wireshark utility.
tcpdump is a packet sniffer. It captures the packets that fly in and out of the machine. tcpdump understands protocols and host names. First thing you have to remember is that you have to login to the server as root or be a sudoer. It is better to redirect the output to a file for debugging purpose. You can play on the recorded file to filter the packets that you are not interested to see. (more…)