[Computer Networks] IPv6

1 IPv6 Overview

introductory

Recently, I've been wondering if I can use an IPv6 public address to do intranet penetration for my NAS at home.

It is technically possible. You just have to make sure that it is an IPv6 public address.

What I learned about IPv6 in college is long gone, so I need to re-learn it and document it.

1.1 Origin: 32-bit`IPv4`Restricted in number and exhausted

192.168.1.1, a string of numbers not unfamiliar to most of us, is a widely used private IPv4 address. It's likely that your home router's management page is set to this address. The router may assign similar private IP addresses to your computers. However, private IP addresses can only be used between devices within a LAN. To access the Internet, you must use a public IP address.
The computer is capable of doing this solely on the basis ofprivate IP addressinterviewspublic IPof the Internet, thanks to theNAT（network address translation) application of the technology. However.NATIt's just a very lame solution for theP2Pconnection or game for that matter seriously deteriorates the network environment. Comparatively speaking, theIPv6Provides an easy-to-use interface that doesn't requireNATof the Internet world, with the ability to assign one or more public IP addresses to each networked device, realizing the true interconnection of everything, as originally envisioned for the Internet.
A common home network environment usually consists of a broadband connection provided by the carrier, an optical cat, and a router purchased by the user. The router is connected to the Internet through thePPPoEdialerAccess to the carrier-assigned public networkIPv4address and also acts as a gateway to the LAN with its own intranet IP address, e.g. 192.168.1.1. All network devices in your home are connected to this router, which is responsible for assigning an intranet IP address to each device, as well as other information such as the default gateway, DNS, and so on.

When accessing an external resource such as Baidu, the browser first requests a resolving IP address from a DNS server. Subsequently, the browser sends a request to that IP address to get the data for the Baidu home page. Since the computer is using a private IP address on the LAN, the router needs to translate the source IP address in the request to a public IP address via NAT before the request can be sent to the Internet. This process solves the problem of insufficient IPv4 addresses, but it also brings many problems such as increased complexity of network communication and destruction of network peer-to-peer connections.
IPv6 was introduced to solve the problem of IPv4 address exhaustion. The address space with IPv4 (2^{32 addresses) compared to IPv6, which offers a virtually unlimited address space (2}128 addresses), which allows each device to have one or more public IP addresses, thus enabling direct communication between devices without NAT.
The configuration process is slightly more complex for IPv6 deployments on home networks. First, you need to make sure your router supports IPv6. most routers purchased within the last two years have IPv6 support turned on by default. The router dials in via PPPoE to obtain a public IPv4 address from the carrier. At the same time, the router will also get a public IPv6 address as well as an IPv6 prefix because IPv6 is turned on.
Summary: The Birth of IPv6

In order to expand the network to meet future demands, it must be able to provide unlimited IP addresses and improve mobility.

IPv6 expands the address space and uses more efficient and feature-rich headers.

Although IPv6 is similar to IPv4, it fulfills the increasingly responsible hierarchical addressing requirements that IPv4 cannot support.

IPv4 vs IPv6

comparison term	IPv4	IPv6
lengths	32 bit	128 bit

1.2 IPv6 address structure

IPv6 address structure

IPv6 Simplified Representation Rules

The 0 at the beginning of each paragraph can be omitted from the text, but the 0 in the middle and at the end cannot be omitted;

Original IPv6 address.3ffe:1944:0100:000a:0000:00bc:2500:0d0b
Simplified IPv6 address.3ffe:1944:100:a:0:bc:2500:d0b

If a segment or consecutive segments are all zeros, a "::" can be used instead.

Raw IPv6 address:ff02:0000:0000:0000:0000:0000:0000:0005
Simplified IPv6 address:ff02::5

If the 128 bits are all 0's the address can be represented by a ":::".

Original IPv6 address.0000:0000:0000:0000:0000:0000:0000:0000
Simplified IPv6 address:::

In an IPv6 address, theYou can only use a double colon once。

Example:2001:0d02:0000:0000:0014:0000:0000:0095, both of the following abbreviations are correct:
2001:d02::14:0:0:95
2001:d02:0:0:14::95

But the following abbreviation is wrong:
2001:d02::14::95

can represent any of the following possible IPv6 addresses:

2001:0d02:0000:0000:0014:0000:0000:0095
2001:0d02:0000:0000:0000:0014:0000:0095
2001:0d02:0000:0014:0000:0000:0000:0095

address classification

unicastAddress: identifies a single node.

global unicast address

A global unicast address typically consists of a 48-bit global routing prefix and a 16-bit subnet ID plus a 64-bit interface ID.
Organizations can use the 16-bit subnet field to create their own local addressing architecture.
This field allows organizations to use up to 65,535 subnets.

Begins with 2000::/3 and is assigned by IANA

Example: 2001::1/64 2001:1::1/64 2001:2::1/64

link-local address

Link-local addresses are restricted and can only communicate with nodes on the same link; they are created using the link-local prefix FF80::/10 and a 64-bit interface ID.

Link-local addresses are used for auto-configuration, neighbor discovery, and router discovery

fe80::fe80::20c:85ff:fe00:7d07

multicastAddress: identifies a set of nodes.
AnycastAddress: identifies a group of nodes where the data stream from the source node is forwarded to the node closest to the source in the group.

Note: The anycast address comes from the global unicast address
Multiple devices use the same anycast address

special address

Local loopback address:::1

Analogously, IPv4's native loopback address:127.0.0.1
Arbitrary network:::(all 0)

1.3 Characteristics of IPv6

IPv6 Features

Larger address space

IPv6 addresses are 128 bits long, IPv4 addresses are 32 bits long.

IPv6's huge address space is larger than the entire IPv4 address space and can accommodate everyone on the planet.

No NAT required

Larger address space for end-to-end communication without NAT.

No broadcast address

IPv6 includes unicast, multicast and anycast addresses.

Support for mobility and security

Helps ensure compliance with mobile IP standards and IPsec standards.

Simpler headers improve router efficiency

What's New in IPv6

▪ Modification of prefixes

IPv6 improves a simplified address and prefix modification mechanism.

Multiple addresses per interface

An IPv6 interface can be assigned several different types of addresses and can be used simultaneously .

link-local address

The IGP uses the link-local address as the next hop when switching route updates.

Stateless autoconfiguration.

DHCP is not required because an IPv6 device can assign a unique link-local IPv6 address to itself.

Provider-independent or non-provider-independent addressing

1.4 IPv6 support requirements

NIC Adapter Support

Network Router Support

Enabling the IPv6 Protocol on the Router

# Enable the IPv6 protocol on the router
R(config)#ipv6 unicast-routing

# Assign an IPv6 address to the interface
R(config)#interface f0/0
R(config-if)#ipv6 address 2001::1/64|2001::/64 eui-64


# ipv6 address R(config-if)#ipv6 address 2001::1/64
show ipv6 interface brief
show ipv6 route

DNS server support

application server support

User Browser Support

due toIPv6Web usage is not particularly extensive, so many browsers will default to configuring theprohibit the use of sth.up IPv6 functionality. Example:Google ChromeThat's just it, even after we access the IPv6 network, we still can't use IPv6 related features.
360 Browser : Support
QQ Browser : Support
Chrome: Supported, but needs to be enabled by the user.

In order to use Chrome's IPv6 feature, we need to make configuration changes to Chrome to enable IPv6.

step1 Type in Chrome's address bar:about:net-internals/#dns maybechrome://net-internals/#dns

step2 Click the Enable Ipv6 button. Now, our Chrome is ready to use IPv6, and after logging into test. again, all the functions are back to normal!
If you think enabling ipv6 is affecting you, you can turn it off. To do so, right click on the chrome shortcut, click on "Properties" and add the following to the "target" address--disable-ipv6 , just restart chrome. Example:

cd /opt/google/chrome
sudo gedit google-chrome

# exec -a "$0" "$HERE/chrome" "--enable-ipv6" "$@"
# exec -a "$0" "$HERE/chrome" "--disable-ipv6" "$@"

maybe：
C:\Users\xxxxxx\AppData\Local\Google\Chrome\Application\ --disable-ipv6

Common Parameters for chrome

--enable-ipv6
Enable ipv6
--disable-ipv6
Disable ipv6

Example.

--disable-async-dns

--disable-images
Disable images

--disable-javascript
Disable javascript

--disable-logging
Disable automatic logging

--disable-sync
Disable automatic synchronization

--disk-cache-dir
ex:"" -disk-cache-dir="X:/"
Specify the cache directory

--disable-java
Disable java

--disk-cache-size
Cache size

User's computer support

Windows Enable/Disable IPv6

Control Panel\Network and Internet\Network and Sharing Center\(select an active Ethernet connection)\(double-click) Connections-(click)causalityTo view the Ethernet properties

Or:Control Panel\Network and Internet\Network and Sharing Center-Change Adapter Settings\(Select an active Ethernet connection)\(Right click)Properties`, to view Ethernet properties

locateInternet Protocol version 6 (TCP/IPv6)option, just check or uncheck it

IPv6 Support Quiz

Windows computer

Control Panel\Network and Internet\Network and Sharing Center\(select an active Ethernet connection)\(double-click) Connections-ViewIPv6 connectivitystatus information

Ethernet connections that do not support IPv6

IPv6-enabled Ethernet connections

Quiz site:

https://test. [Recommended

[Recommended

is a free service that checks your IPv6 and IPv4 connections and speeds. Diagnose connection problems and find out which addresses you are currently using to browse the Internet and what protocol your browser chooses when both v6 and v4 are available.

/.zh_CN

/find

Shaped as:/find/2400:DA00:2::29

X References

[Network] Discriminating and Classifying IP Addresses for Internal and External Networks (IPv4) - Blogspot/Children's Universe
How to turn on or off IPv6 in Chrome - Baidu Wenku
IPV6 - CSDN
IPv6 Support - China Tech Cloud Pass
An Introduction to Public IP for Everyone - IPv6 - What's Worth Buying [Recommended
What web pages can ipv6 access? - Baidu

Accessed at: 2400:da00:2::29
...

/ipv6/ [Recommended