For internet communication over Ethernet, a Transmission Control protocol/Internetprotocol (TCP/IP) software stack is necessary. This stack resides on the Host MCU. Microchip offers a free TCP/IP stack that includes all the major protocols necessary from the physical Ethernet layer up to and including the presentation or application layer. Stack version 2.20 is Royalty-free with no license cost. It can be download from the microchip web site. It is about 25kB of code and modular in design so that you can pick and choose the protocols according to the application need. It is portable to all PIC18 micros and has supporting documentation for more information regarding the stack.