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A record vs AAAA record: which DNS address type you need
Clear difference between DNS A (IPv4) and AAAA (IPv6) records, when you need both, and how to verify them with a free DNS lookup.
An A record maps a hostname to an IPv4 address (for example 203.0.113.10). An AAAA record maps the same idea to an IPv6 address (for example 2001:db8::1). Dual-stack sites publish both so clients can connect on either family.
When A alone is enough
Many small sites still run IPv4-only. That works for most users, but IPv6-only networks (some mobiles and ISPs) may fail to reach you. If your host or CDN offers a free IPv6 address, adding AAAA is usually low risk once the web server listens on IPv6.
When AAAA causes surprises
- AAAA points to a host that does not serve HTTPS → browsers on IPv6 fail while IPv4 works
- Broken IPv6 routing at the VPS → intermittent “site down” only for some users
- Mail: MX targets need working A/AAAA for the MX hostname, not only the apex
See both address families for your hostname in one lookup.
Quick verification habit
After publishing AAAA, open the site from an IPv6-capable path (or ask a colleague on a different ISP). Confirm the certificate SAN still matches. Propagation checks help when only some resolvers show the new AAAA.