As TCP/IP is what governs almost all modern networks, it is a good idea to learn TCP/IP if you are either a system or a network administrator. I suggest the following steps for learning TCP/IP and its protocols:
- Make simple connections using telnet to better understand a protocol.
- Study relevant RFCs to fully understand a protocol.
- Read books.
- Make more complex TCP/IP connections using telnet.
- Study the network traffic and the TCP/IP packets using WireShark.