# NETWORKING & INTERNET ? THE NETWORK BEHIND EVERYTHING

We use it every day.

But have you ever stopped to think about what actually happens when you
type an address into your browser?

============================================================================== WHAT HAPPENS WHEN YOU CONNECT?
==============================

You type:

```
example.com
```

Your computer asks DNS:

```
"Where is example.com?"
```

DNS returns an IP address.

Your computer then establishes a connection to the remote server.

Routers move your packets across multiple networks until they reach their destination.

The server responds.

And somehow all of this usually happens in a fraction of a second.

============================================================================== IPv4 & IPv6
===========

The Internet was originally built primarily around IPv4 addresses.

Example:

```
192.168.1.100
```

IPv4 provides roughly 4.3 billion possible addresses.

That sounded like an absurdly large number decades ago.

Then we connected...

Computers.
Phones.
Servers.
TVs.
Game consoles.
Cameras.
Cars.
Thermostats.
Doorbells.
Light bulbs.

Oops.

IPv6 provides an enormously larger address space.

Example:

```
2001:db8:1234:5678::1
```

The number of available IPv6 addresses is so large that ordinary
IPv4-style address exhaustion essentially disappears.

============================================================================== KNOW YOUR PORTS
===============

Some classic TCP/UDP ports every networking geek eventually encounters:

20/21 FTP
22 SSH
23 Telnet
25 SMTP
53 DNS
67/68 DHCP
80 HTTP
110 POP3
143 IMAP
443 HTTPS
513 RLogin

And, of course...

There is no law saying your BBS has to run Telnet on port 23. ;)

============================================================================== YOUR HOME NETWORK
=================

A typical home network now includes:

```
Internet
|
Modem / ONT
|
Router
|
+-----+-----+
| |
Ethernet Wi-Fi
| |
Computers Phones
Servers Tablets
NAS TVs
Printers IoT
```

============================================================================== WIRED STILL MATTERS
===================

Wi-Fi is fantastic.

But when reliability and consistent performance really matter:

```
RUN A CABLE.
```

Servers, NAS systems, gaming machines and high-bandwidth workstations
often benefit from good old-fashioned Ethernet.

Sometimes the best wireless connection...

```
...is a wire. ;)
```

============================================================================== THE INTERNET LIVES!
===================

From 300-baud modems to fiber connections capable of multiple gigabits
per second, networking has come an unbelievable distance.

But underneath all the fancy applications, we're still doing the same
basic thing:

```
MOVING BITS FROM ONE MACHINE TO ANOTHER.
```

============================================================================== --- ANetBBS
* Origin: ANetBBS - A Modern BBS System (1200:1/1)