Developing Client/Server On A Non-Application Layer

Question

How can I develop a network application (client/server) that will work in the transport or network layers of the ISO OSI model? For example: if I don't wan't the system to pack a data in a TCP or UDP packet, but instead I want to use my own protocol? How can I achieve that?

Help will be very appreciated!

Answer 1

For the transport layer you should use raw sockets.

For the network layer you could use e.g. libpcap. See here for a simple HOWTO.