IPv6 Address: Public vs Private

Updated on Sep 29, 2021 by

As we know, every networking device must have an IP address to access the Internet. The exhaustion of the IPv4 address space is primarily due to the uneven allocation and wastage of IPv4 addresses over the years. Therefore IPv6 is developed to create more unique IP addresses for these devices. The IPv6 address is similar to IPv4 in concept, but it provides far more than enough unique IP addresses for worldwide networking devices such as computer, router, data switch, etc. This article offers a detailed introduction to IPv6 addresses and explores the differences between public and private IPv6 addresses. For more information on differences between IPv6 and IPv4, please read IPv4 vs IPv6: What’s the Difference?

What Is IPv6 Address?

IPv6 is short for Internet Protocol Version 6, which is the latest version of the Internet Protocol (IP). Like IP, IPv6 is a packet-based protocol used for exchanging data, voice, and video traffic over the digital network. It uses 128-bit addresses and provides about 340 undecillion IP addresses. As shown in the following figure, IPv6 consists of eight numbered strings, each containing four characters (alphanumeric), separated by colon.

IPv6 Address Types

IPv6 supports three address types: unicast, multicast, and anycast. Unicast IPv6 address allows a packet delivered to one interface. When it comes to the multicast IPv6 address, the packet is delivered to multiple interfaces. Anycast IPv6 address makes a package delivered to the nearest of multiple interfaces (in terms of routing distance). Among them, unicast and multicast IPv6 addresses support address scoping, which identifies the application suitable for the address.

 Features  Unicast  Multicast  Anycast
 Data Transmission Target  Single receiver (one-to-one)  Multiple receivers (one-to-many)  Nearest receiver (one-to-one)
 Routing Protocol Support  Unicast routing protocols (such as OSPFv3, BGP)   Multicast routing protocols (such as PIM, MLD)  Distributed routing protocols (such as OSPFv3, BGP)

 Global unicast addresses: 2000::/3

Unique local addresses: FC00::/7 or FD00::/7

Link-local addresses: FE80::/10

 FF00::/8  N/A
 Application Scenarios  Point-to-point communication, unicast services  Multimedia streaming, distributed applications Resource discovery, load balancing

How to Check the IPv6 Address?

For a device/network:

  • Use your browser: Search "What is my IP" on Google and check the rich snippet with the IPv6 address.

  • Windows: Open Command Prompt and type "ipconfig" to view the entire IP configuration.

  • Linux: Open Terminal and type "ip addr" to find the "inet" section displaying the IPv6 address.

  • MacOS: Click the Apple icon, go to "System Preferences," select "Network," choose your network connection, and find the IPv6 address.

For the hostname:

  • Windows: Open Command Prompt and use the command "nslookup -type=aaaa hostname" (replace "hostname" with the desired hostname) to get the IPv6 address(es).

  • MacOS/Linux: Open Terminal and use the command "dig hostname aaaa" (replace "hostname" with the desired hostname) to retrieve and check the IPv6 address.

IPv6 Address: Public vs Private

Both public and private addresses exist in IPv6, but they are totally different in definition and application.

What Is A Public IPv6 Address?

A public IPv6 address is an IP address which is accessible by anyone on the Internet. To avoid upsetting the order, the public IPv6 address is often globally unique. It can only be assigned to a unique device such as a web server, an email server or any server device directly accessible from the Internet. Therefore, the public IPv6 address is usually provided by the Internet Service Provider (ISP).

What Is Private IPv6 Address?

Taking up a small part of the massive IPv6 address space, the private IPv6 is for special requirements and private use in IPv6 networks. These private IPv6 addresses are only local to a specific link or site, therefore they are never routed outside a particular network. Based on their scope, private IPv6 addresses can further be divided into site-local and link-local addresses. The site-local address has the scope of an entire site or organization. Link-local address, on the other hand, has a smaller scope and only refers to a particular physical link.

What’s the Difference Between Public and Private IPv6 Addresses?

When we have a look at them, we realize that the main difference between public and private IPv6 addresses lies in their scope. To be more concise, the public IPv6 address looks at a global scope, while the private IPv6 address is for a local network. Due to this, public and private IPv6 addresses also have the following differences:

Public IPv6 Address Private IPv6 Address
Connected with the Internet network Connected with a LAN
Publicly registered with Network Information Center Is not registered with Network Information Center
Requires Modem to connect to a network Requires network switch to connect to a network
Assigned by the ISP to identify a home or business network from the outside Allotted by the client and are given by the client’s switch such as a Gigabit Ethernet switch

Benefits of IPv6

  • More available addresses: IPv6 offers a larger address space, accommodating the increasing number of devices connected to the Internet.

  • Efficient routing: IPv6 has an organized routing scheme, resulting in more efficient routing tables for improved network performance.

  • Enhanced data flow: IPv6 enables faster transfer of large data packets, preserving bandwidth and improving data transmission efficiency.

  • Built-in security: IPv6 includes improved authentication methods and encryption, enhancing network security and protecting data confidentiality and authenticity.

How Enterprises Upgrade to IPv6

  • Dual stack: Implement both IPv4 and IPv6 on network nodes, allowing them to run both protocols simultaneously.

  • Tunnels: Carry IPv6 packets over existing IPv4 infrastructure by encapsulating them within IPv4 packets.

  • Translation: Use gateways to perform address translation between IPv4 and IPv6, enabling communication between the two address structures.

  • Another approach is to allow network nodes to select the protocol they can use, relying on dual-stack routers, NAT, and IPv4 tunnels for address translation as needed.

Network Switches Supporting IPv6

If you are looking for network switches that supports IPv6, here are three high-performance switches from FS, a global high-tech company providing high-speed communication network solutions and services.

   S5810-28FS   S3900-48T4S  S5800-48F4SR
 Management Layer  Layer 3  Layer 2+  Layer 3
 Ports  28 x 1Gb SFP, with 4 x 10Gb SFP+ Uplinks  48 x Gigabit RJ45, with 4 x 10Gb SFP+ Uplinks  48 x 1Gb SFP, with 4 x 10Gb SFP+
 Key Features  Support IPv6, CLI, WEB, SNMP, SSH, etc.  Support IPv6, CLI, WEB, SNMP, SSH, etc. Support IPv6, CLI, WEB, SNMP, SSH, etc.


Now many ISPs, websites and manufacturers are supporting IPv6, and we will be inevitably switching to an IPv6 address. When preparing your network for IPv6, do not forget to use the IPv6 compatible hardware and software, especially network switches supporting IPv6 forwarding. FS provides a series of 1G and 10G switches that support both IPv4 and IPv6 addresses. They also comprise of advanced features including MLAG, SFLOW, SNMP, etc. For more information, please visit our website www.fs.com.

Related Articles:

How to Understand IP Address and Subnet Mask?

DHCP vs Static IP: Which One Is Better?

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