What is IPv6 and what advantages does it offer?

Before the introduction of domains as internet addresses, connecting to a single server within a network was done solely through a direct call. The address used was the numerical IP address, which is readable by computers and allows for a subdivision into different subnets and areas, providing a hierarchical order. After more than two decades of development, since around 2015, Internet Protocol Version 6 (IPv6) has been replacing the former standard Version 4 (IPv4), offering numerous advantages over its predecessor.

What is DNS and what task does it perform?

The IP address consists of a decimal or hexadecimal number, composed of different elements. These are separated by a special character such as . or : and divide the entire network into different zones and subnets. Certain address ranges are reserved by standards for specific purposes such as local connections, test networks, or private, non-public use. All communication between servers and clients occurs on a technical level exclusively through IP addresses. The conversion from a Fully Qualified Domain Name (FQDN) like example.org to a numerical IPv4 or IPv6 address is handled by the Internet-implemented Domain Name System (DNS).

Before a client such as a browser accesses a website, it sends a request to the DNS to find out under which IP address it can be reached. Whether it uses IPv4 or IPv6 primarily depends on the chosen connection and the provider's technology. To ensure maximum reachability, both systems exist in parallel and can be used simultaneously - if the chosen standard procedure fails with an error message, the client or the operating system will attempt with the other version if both an IPv6 and an IPv4 connection are available.

How does address resolution work with IPv4 and IPv6?

The resolution of a domain by the DNS is done through a network of nameservers that are hierarchically responsible at different levels for a Top Level Domain (TLD), a name, a network, or the domain addresses managed by a web host. When a request is made, the client first asks a Root DNS Server for the responsible nameserver and progresses from the top instance to a specific, unique address. It then uses this as the target and establishes a connection to a running web service such as HTTP, SSH, or FTP.

What are the advantages of IPv6 over IPv4?

The main reason for the introduction of IPv6 lies in the limited address space of IPv4, which uses only a resolution of four times 8 bits. Subtracting the areas reserved for special purposes, this results in a maximum of about 3.5 billion unique combinations, which proves to be insufficient given the exponential growth of the Internet and connected devices. In contrast, IPv6 uses a 128-bit long, hexadecimal number, providing theoretically more than 340 undecillion - a number with 38 zeros - available. However, additional benefits arise from extra features such as:

• Unique and unambiguous identification of all participants in the network
• Faster resolution by avoiding local networks (NAT)
• Additional prefixes for distinguishing networks and subnets
• Greater number of special addresses and address spaces
• Parallel operation of IPv4 and IPv6 possible
• Direct communication via IPv6 addresses without subsequent routing

In general, it is advisable to primarily use an IPv6 address for your own Virtual Private Server (VPS) or dedicated Dedicated Server, as it offers better performance and now higher compatibility. Due to the multitude of available combinations, web hosts also offer these at a low cost, allowing for the assignment of multiple IP addresses to a single server without significant expense. This enables the server to act as multiple autonomous instances, facilitating tasks such as distributing network traffic or directly assigning individual websites to a fixed IPv6 address to improve the Server Response Time and minimise resource consumption for packet processing.

Photo: Kevin Morison on Pixabay