When to add a dedicated IPv4

2 min read07 November 2026

NeoHeberg includes IPv6 on every VPS and offers a dedicated IPv4 as a paid option. Many projects work well on IPv6 alone; others lose part of their audience or integrations without IPv4. The right question is not "which address is better", but "who must reach this service, and over which stack".

What missing IPv4 changes

Without IPv4, your machine is reachable only by clients that have IPv6. A user whose provider does not route IPv6, an older corporate network or a third-party service that only resolves A records will see nothing. The service exists but is invisible to them. No server setting fixes that: you need an IPv4 address.

Cases that need IPv4

Situation	IPv4 useful?
Public marketing site	Yes, some visitors only have IPv4
API called by third parties	Often yes, check their requirements
Incoming webhooks and callbacks	Yes if the provider only publishes `A` records
Outgoing email	Yes, deliverability still largely relies on IPv4
Outbound-only service to IPv6 targets	No, if the target is reachable over IPv6
External monitoring	Depends on the tool

Dual stack and DNS

With both addresses, publish an A and an AAAA record for the same name. Modern clients use Happy Eyeballs: they try both and keep the connection that answers fastest. This is normal and can make traffic appear to switch addresses.

Bash

dig +short A votre-domaine.fr
dig +short AAAA votre-domaine.fr
curl -4 -I http://votre-domaine.fr/
curl -6 -I http://votre-domaine.fr/

All four commands should answer. If curl -4 fails while curl -6 works, the A record or the IPv4 firewall is at fault.

Enable the option

Add IPv4 from the dashboard on the VPS page, according to the plan options. The address may require network reconfiguration or a reboot: keep the console open and record the current configuration before starting. The option price appears on the service page, not in this guide.

Check both paths

After activation, check the address with ip -4 addr show, then test a real service from outside, over IPv4 and IPv6. Do not rely on a ping: a firewall can allow ICMP and block the application port. Record both addresses in your notes, because a migration or DNS change will make them essential.