Port forwarding facts for kids
Port forwarding, also called port mapping, is a clever way to send information from one computer network to another. Imagine your home network as a big apartment building. Port forwarding helps outside visitors (like people on the internet) find a specific apartment (a computer or device) inside your building, even though your building only has one main address (your router's public IP address).
This technique lets computers from the internet connect directly to a specific computer inside your private home network. It's often used when you want to run a game server, a website, or access your home computer from outside.
For example, you might use port forwarding to:
- Let people on the internet see a website you're running on your computer.
- Allow you to securely connect to your home computer from school or a friend's house.
- Set up a game server so your friends can join your game.
Port forwarding isn't needed for newer internet addresses called IPv6. That's because every device with an IPv6 address has its own unique public address, so they can be found directly without any special forwarding.
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What is Port Forwarding?
Port forwarding is a way for your router to direct incoming internet traffic to a specific device on your home network. Think of your router as a doorman for your house. When a package (data) arrives, the doorman needs to know which room (device) to send it to.
How Does Your Router Work?
Your home network usually has one main internet address, called a NAT-enabled router. This router acts like a translator. It lets many devices inside your home (like your computer, phone, and game console) share one internet connection. When you connect to a website, your router remembers which device asked for the information and sends it back to the right one.
Connecting from Outside
When someone from outside your home network wants to connect to one of your devices, it's a bit different. They can only see your router's main internet address. They can't directly see the individual devices inside your home network. This is where port forwarding comes in handy.
Why Do We Use Port Forwarding?
We use port forwarding to allow specific types of connections to reach specific devices on our private network. Without it, your router would block most incoming connections from the internet for safety reasons.
Common Uses for Port Forwarding
- Web Servers: If you want to host your own website from your computer, port forwarding directs web traffic (usually on port 80) from the internet to your computer.
- Game Servers: Many online games let you host your own game server. Port forwarding helps your friends connect to your game server from their homes.
- Remote Access: Tools like Secure Shell (SSH) let you securely control your computer from another location. Port forwarding makes sure these connections reach your computer.
- File Sharing: If you use FTP (File Transfer Protocol) to share files, port forwarding helps others connect to your file server.
How Does Port Forwarding Work?
When you set up port forwarding, you tell your router two main things:
- Which "port number" to listen for from the internet.
- Which specific device (using its private IP address) on your home network should receive the traffic for that port.
A Simple Example
Imagine you have a game server running on your computer. You tell your router: "If any internet traffic comes in on port 25565 (a common Minecraft port), send it to my computer at its internal address, like 192.168.1.100."
When your friend tries to connect to your game, their computer sends a request to your router's public internet address, specifying port 25565. Your router sees this, remembers your rule, and sends that request directly to your computer.
Port Forwarding and IPv6
IPv6 is the newest version of internet addresses. With IPv6, every device can have its own unique public address. This means that devices can be reached directly from the internet without needing a router to "forward" connections. Because of this, port forwarding is not usually needed for IPv6 connections.
Related pages
See also
In Spanish: Redirección de puertos para niños
