The scenario is that you’re connected to a remote machine via ssh and you want to run tcpdump and view the output in real time. Unfortunately, the output will include the ssh connection information as well and therefore it’s quite useless. The simple solution is to filter out ssh:

tcpdump [options] not port ssh

Thanks to http://forum.soft32.com/linux2/tcpdump-filter-examples-ftopict29715.html.