Suggest an editImprove this articleRefine the answer for “How does IPv4 differ from IPv6?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**IPv4 and IPv6** are two versions of the IP protocol that solve the same task (addressing and delivering packets), but **differ greatly in capabilities and structure**. **Key point:** IPv6 is a modern, expanded version of IPv4, created because of address exhaustion and IPv4's technical limitations.Shown above the full answer for quick recall.Answer (EN)Image**IPv4 and IPv6** are two versions of the IP protocol that solve the same task (addressing and delivering packets), but **differ greatly in capabilities and structure**. Short version: **IPv6 is a modern, expanded version of IPv4, created because of address exhaustion and IPv4's technical limitations**. --- ## Main differences between IPv4 and IPv6 ### 1. **Address space size** The most important difference. - **IPv4** - address length: **32 bits** - ~4.3 billion addresses - addresses have practically run out - **IPv6** - address length: **128 bits** - a huge number of addresses - no address shortage --- ### 2. **Address notation** - **IPv4** ``` 192.168.1.10 ``` - decimal notation - 4 numbers of 8 bits each - **IPv6** ``` 2001:db8::1 ``` - hexadecimal notation - 8 groups of 16 bits each - shortening is allowed (`::`) --- ### 3. **Broadcast and multicast** - **IPv4** - has **broadcast** - has multicast - **IPv6** - **no broadcast** - only **multicast** and unicast are used This reduces unnecessary traffic on the network. --- ### 4. **NAT** - **IPv4** - **NAT** is widely used - one public IP for many devices - **IPv6** - NAT **is not needed** - each device can have a public address --- ### 5. **Packet header** - **IPv4** - variable header length - more complex processing - **IPv6** - fixed header - simplified routing - extra fields moved into extensions --- ### 6. **Autoconfiguration** - **IPv4** - usually needs DHCP - or manual configuration - **IPv6** - built-in **autoconfiguration (SLAAC)** - can work without DHCP --- ### 7. **Security** - **IPv4** - IPsec is not mandatory - **IPv6** - IPsec is built into the standard - security is designed in from the start --- ## Short table of differences | Characteristic | IPv4 | IPv6 | |---|---|---| | Address length | 32 bits | 128 bits | | Format | Decimal | Hexadecimal | | Number of addresses | Limited | Huge | | Broadcast | Yes | No | | NAT | Widely used | Not required | | Header | Variable | Fixed | | Autoconfiguration | Limited | Built-in | --- ## What is important for an interview - IPv6 **is not backward compatible** with IPv4 - for interoperability, these are used: - dual stack - tunneling - translation --- ## In short, for an interview > **IPv6 differs from IPv4 in its larger address space, lack of broadcast, simplified header, built-in autoconfiguration, and reduced need for NAT, which makes it more scalable and modern.**For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.