There are a few important terms that deserve explanation. It is very important that you read this information thoroughly. If you can't understand a term, that's OK, you'll probably pick it up when you see its context throughout the rest of the tutorial and site. Refer back to this article whenever you need an unfamiliar term explained.

IP Address
Every computer has an IP address. It is usually in the form of ###.###.###.### when connecting to external computers. You can connect to 127.0.0.1, a local address, when testing your client and server on the same PC. Your clients will connect to the IP address of your server.

Port
A port is an opening that data can flow through from the connection to a specific program. Port values range from 0 to 65535. Many of the values are assigned to other programs that might be running on your PC, from messenger and VOIP programs to basic web protocols and games. It is recommended that you choose any value between 45000 and 65000 to use as your port.

Packet
A packet is made up of several parts, but for the sake of simplicity think of a packet as a "message". If a client needs to tell the server something, you make it send a packet. A packet contains information, by default, such as the IP address the packet is heading to and which port it is using. A packet also contains data you specify, the message you want to tell the server.

Buffer
Data is written to a buffer before being sent to either the server or clients. Information stored on a buffer can be encrypted, and read from, copied and appended to. When you send data written to a buffer, you are sending it as a packet. Think of the buffer as not only a place to compile packets, but also as a place where they are received and read.

Socket
A socket handles data transmissions for individual connections. When a client connects to the server, they are assigned a socket on the server side. Data is received from this socket when a client sends a message to the server, and data is sent through this socket when the server wants to send a specific client data.

TCP (Transmission Control Protocol)
A method of sending packets which practically guarantees that the message arrives. We will make use of this protocol throughout the entirety of this tutorial and site.

UDP (User Datagram Protocol)
A method of sending packets which is fast, but does not guarantee their arrival or the correct order of details.

Lag
The time it takes for a packet to make a round trip between client and server.

Ping
The shortest possible time it takes to send data between a client and the server. Ping is commonly measured in milliseconds; a low ping is best.

Make sure you have a basic understanding of each of the above terms, especially packets, before continuing.