Quiz Entry - updated: 2026.07.14
What are the key improvements IPv6 offers over IPv4?
Bigger address space (no NAT), stateless autoconfiguration, a simpler fixed header, no in-transit fragmentation, built-in IPsec, and QoS support via flow labels.
The six headline improvements:
| # | Improvement | Why it matters |
|---|---|---|
| 1 | Stateless address autoconfiguration (SLAAC) | Hosts self-configure without a DHCP server |
| 2 | 128-bit addresses, NAT eliminated | Restores true end-to-end addressing |
| 3 | Simplified header | Less per-packet processing on routers |
| 4 | No fragmentation by routers | Routing is more efficient; only the source fragments |
| 5 | Built-in IPsec | Security designed into the protocol (extension headers) |
| 6 | Built-in QoS | Flow labels let routers prioritise delay-sensitive traffic |
Tip: In practice the killer feature is simply the address space — most of the others (IPsec, QoS) also exist as bolt-ons in IPv4, but you can't bolt on more addresses.
Go deeper:
IPv6 (Wikipedia) — the canonical list of IPv6 improvements (simpler header, SLAAC, multicast, no router fragmentation).- RFC 8200 — IPv6 Specification — the authoritative spec the improvements derive from.