
Be prepared, however, to sift through a large number of packets because the
server response can actually take place over multiple packets. If you’re using
Ethereal, be sure to take advantage of its filtering and coloring rules to sort the
chaff from the wheat.
At some point, you’ll need to actually modify the packets, not just view them,
and this takes more than a sniffer.There are several different ways of modifying
packets, and both are used extensively. For a “one-off ” request, simple Telnet will
do the trick; simply Telnet to the server on port 80 (or the appropriate port), type
in your packet, and terminate the packet with two carriage returns; ...