sorting of tcpdump output

Hi! I took a tcpdump of a some kind of strange connection (a permanently 24/7 connected station) and want to sort the content from the content I don't want to read (only the one station is of interest, the rest can got to /dev/trash). I only want to knwo, what he/she is doing, or if he/she forgot to logout of an web-app. I used less | grep -e FILTER1 -e FILTER2 [...] > output, but grep anly shows me single lines. Is there any other programm that can filter the output or any tools on the net? Philippe