tcpdump: syntax error [need help]

sudo tcpdump -s 3600 -q -nxS -i en1 'ip and port 80' -w - | strings

this gives me a

tcpdump: syntax error

and i dont know why.

plz help
thanks a lot
andrew :wink:

make sure that "'ip and port 80'" is the last argument. all options must be before the filter. see the usage.