Tech Bits: IPv4 vs IPv6

Other Tech Bits Posts

What is an IP Address?

An IP address (Internet Protocol address) is a unique numerical label assigned to each device connected to a network. It serves two main functions:

1. Identification – It uniquely identifies a device on a network.
2. Location Addressing – It helps route data between devices over the internet.

Every device that connects to the internet, from smartphones to servers, requires an IP address to communicate. The two main types of IP addresses in use today are IPv4 (Internet Protocol version 4) and IPv6 (Internet Protocol version 6).

IPv4 vs. IPv6: Key Differences

IPv4 has been the backbone of internet communications for decades, but with the explosion of internet-connected devices, IPv6 was developed to accommodate the growing demand. Can you believe that IPv6 is also 20+ years old?

Feature	IPv4	IPv6
Address Length	32-bit	128-bit
Address Format	Dotted decimal (e.g., 192.168.1.1)	Hexadecimal colon-separated (e.g., 2001:db8::1)
Number of Addresses	~4.3 billion	~340 undecillion (virtually unlimited)
Header Complexity	More complex	Simplified for efficiency
Security	Optional (IPsec available)	Built-in IPsec support
NAT (Network Address Translation)	Commonly used due to address exhaustion	Not needed due to a larger address space
Auto-Configuration	Uses DHCP	Supports stateless autoconfiguration (SLAAC)

The main reason for transitioning to IPv6 is the exhaustion of IPv4 addresses, which limits the number of devices that can be connected directly to the internet.

How to Ping an IPv4 or IPv6 Address

Pinging an IP address is a useful way to check if a device is reachable on the network.

For IPv4:

On Windows/Linux/macOS, use:

ping 192.168.1.1

For IPv6:

On Windows:

ping -6 2001:db8::1

On Linux/macOS:

ping6 2001:db8::1

If you're using a link-local IPv6 address (starting with fe80::), you must specify the network interface:

ping6 fe80::1%eth0

Replace eth0 with your actual interface name (e.g., wlan0 for Wi-Fi).

Using an IP Address in a Browser Address Bar

You can directly enter an IP address into a web browser’s address bar to access a website or a device’s web interface.

For IPv4:

http://192.168.1.1/

This is common for accessing router configuration pages.

For IPv6:

IPv6 addresses must be enclosed in square brackets:

http://[2001:db8::1]/

If a specific port is required:

http://[2001:db8::1]:8080/

Challenges in Mixed IPv4 and IPv6 Networks

Many local area networks (LANs) operate in a dual-stack environment, meaning they support both IPv4 and IPv6. However, this can introduce some challenges:

1. Compatibility Issues – Some older devices and software do not support IPv6, requiring a fallback to IPv4.
2. Routing Complexity – Managing both IPv4 and IPv6 traffic can require additional network configuration.
3. DNS Resolution Conflicts – Devices may receive both an IPv4 and IPv6 response when resolving a hostname, and network behavior can be unpredictable. <-- This is the biggest risk you want to watch out for!
4. Security Considerations – IPv6’s built-in security features (e.g., IPsec) might not be implemented correctly, leading to potential vulnerabilities.

What Happens if IPv6 is Disabled on the Router?

If IPv6 is disabled on a router, devices in the network will only use IPv4 for communication. This can limit connectivity to IPv6-only services and may cause compatibility issues in mixed networks. Enabling dual-stack is recommended for full compatibility. However, for a home network where you have a limited number of networking devices, this might be a good thing!

Other Tech Bits Posts

Picture of the Day:

P.S. Remember, the easiest way to keep up with my journey is by visiting blog.lannyland.com