What is IPv6?

You do not need to memorize the numbers. Picture how a request from outside finds a device inside your home.

Example: a building with many rooms

Someone outside wants to call a particular room. The way to call depends on whether each room has its own number or calls go through reception.

IPv4 is like one shared reception number

IPv4 is usually one shared address for the whole home. An outside call must ask reception, meaning the modem, to forward it to the right room; this is called port forwarding or NAT. Some connections reuse one address across several homes, so you cannot forward a port yourself and may need IPv6 or another option.

IPv6 is like a separate number for each room

With IPv6, each device can have its own address, so a call can go directly without NAT-style forwarding. However, the modem often keeps the inbound door locked, so you still need to allow the right device and port through the IPv6 firewall.

Why do you still need a Niti name?

IPv6 addresses are long and hard to remember. The ISP may also change the first part of the address when the network changes. A name such as <name>.niti.vn follows the new address, so you do not have to re-enter the long number.

Quick comparison

Comparison	IPv4	IPv6
Address length	Short and familiar, for example 203.0.113.10.	Longer, for example 2001:db8::10.
Port forwarding needed?	Usually yes, so NAT can reach the device.	No NAT is needed, but the IPv6 firewall usually must allow the traffic.
Can each device have its own address?	Devices usually share the modem's public address.	A device can have its own public address.
What does the viewer need?	An IPv4 connection and the correct forwarded port.	The viewer's network must also have IPv6.

Next, see how to use IPv6 for different devices.