SwiftNetScanIPv4 vs IPv6
IPv4 has 32-bit addresses and ran out of space years ago; IPv6 uses 128 bits and removes the need for carrier NAT. Both run side by side on most networks today.
Short answer
IPv6 offers vastly more addresses, simpler headers and end-to-end connectivity without NAT. Raw speed is similar, but IPv6 often avoids extra translation hops.
IPv4 vs IPv6 at a glance
| Attribute | IPv4 | IPv6 |
|---|---|---|
| Address length | 32-bit | 128-bit |
| Address count | ~4.3 billion | 3.4 × 10^38 |
| Notation | 192.168.1.10 | 2001:db8::10 |
| NAT required | Almost always | No |
| Header | Variable, checksummed | Fixed 40 bytes, no checksum |
| Autoconfiguration | DHCP | SLAAC or DHCPv6 |
| Multicast / broadcast | Broadcast used | Multicast only |
| Deployment | Universal | ~45% of Google traffic |
Pros and cons
IPv4
- Works everywhere
- Simple to reason about
- Every tool supports it
- Exhausted address space
- CGNAT breaks inbound connections
- Extra translation latency
IPv6
- Effectively unlimited addresses
- No CGNAT penalty
- Cleaner routing and headers
- Longer, harder-to-type addresses
- Some legacy gear lacks support
- Firewall rules must be duplicated
Which should you choose?
| If this is you | Pick |
|---|---|
| Hosting a game or media server at home | IPv6 |
| Connecting to legacy corporate VPNs | IPv4 |
| Mobile networks | IPv6 |
| Maximum compatibility | Dual stack |