sudo apt-get install tcpflow sudo tcpflow -p -c -i <netinterface> port <portnum> # Example: tcpflow -p -c -i eth0 port 80
TCPFlow tool help me to sniff tcp communication on any port (source or target). It could be combined with "grep" to filter text while running. <netinterface> is the network interface's name, it could by "any" or name like "eth0", "wlan1" etc. <portnum> is the port number to be tracked (it does not matter if is source or target port).