tcpdump command used to get details of traffic on network.
To get tcp dump on port 8080 use following command:
$ tcpdump -i eth0 'port 8080'
To run tcpdump command root permission is must. So you need to log as root or use sudo to run above command.
It will display all traffic coming to port 8080 of eth0.
tcpudmp by default snarf’s 68 bytes of data from each packet. To snarf more data use -s option with tcpdump.
$ tcpdump -s 1000 -i eth0 'port 8080'