Is there some example in ethercard.h or some other library for enc28j60, that I can communicate with the computer as a client and the ethernet shield enc28j60 as a server?
These links are not suitable for this purpose. Can someone suggest something else?
The UIPEthernet library is API compatible with the Arduino Ethernet library. This means that you don't need to restrict your search to code specifically written for ENC28J60. If you find code that will do what you want written for the Ethernet library, you can simply install the UIPEthernet library and change the #include directives and that code written for the Ethernet library should also work on your ENC28J60. I have found it's not always quite so simple as that, but it's worth a try.
Ιf I run the backsoon code found in examples of library ethercard.h, and just change the library to the code from ethercard.h to UIPEthernet.h, and using the enc28j60 will run?Is that what you recommend?
No. The EtherCard library has its own unique API. If you find code written for EtherCard, then just use it with EtherCard.
What I'm trying to tell you is that there is tremendously more code available on the Internet which was written for the official Arduino Ethernet library (which is for the W5x00 Ethernet controller chips). You're more likely to get good search results if you don't limit your search to only code written for ENC28J60. If you find some code you like that was written for the Ethernet (note I said Ethernet, not EtherCard) library, then you should be able to easily convert that code for use with the UIPEthernet library (which is for ENC28J60).
Thank you very much pert!!!