Setting up a new VPS for a web app, wondering if IPv6 is mandatory

IPv6 is not mandatory for most web applications today, but enabling it is strongly recommended for future-proofing and accessibility. While IPv4 still dominates, IPv6 adoption is growing rapidly (now exceeding 40% globally), and some networks, particularly mobile carriers, are IPv6-only. Without IPv6 enabled, users on these networks will require carrier-grade NAT translation to access your IPv4-only server, which can introduce latency, connection issues, or outright failures. Enabling it now is a simple preventative measure that ensures all users have a direct, optimal connection path.

Enabling IPv6 is typically straightforward. First, check if your VPS provider has assigned you an address (often in the control panel). Then, configure your firewall to allow IPv6 traffic. For `ufw`, use:

sudo ufw allow proto tcp from any to any port 80,443

Finally, ensure your web server listens on IPv6. In Nginx, your `listen` directive should include:

listen [::]:80;\nlisten [::]:443 ssl;

A quick restart of Nginx and your firewall will activate the dual-stack configuration, serving both protocol versions without impacting your existing IPv4 setup.