IPv6
IPv6 (128 bits)
IPv6 (Internet Protocol Version 6) is the newest version of the Internet Protocol used to identify devices and route data across networks and the Internet. It was created to replace IPv4, which is running out of available addresses.
Why was IPv6 created?
IPv4 uses 32-bit addresses and supports about 4.3 billion unique addresses. With billions of computers, phones, servers, IoT devices, and smart devices connected to the Internet, more addresses were needed.
IPv6 uses 128-bit addresses, providing approximately:
340 undecillion addresses
(340,282,366,920,938,463,463,374,607,431,768,211,456 addresses)
This is more than enough for the foreseeable future.
IPv4 vs IPv6
Feature IPv4 IPv6Address Length 32-bit 128-bit
Format 192.168.1.1 2001:0db8:85a3::8a2e:0370:7334
Address Space ~4.3 billion ~340 undecillion
NAT Required Often Usually not
Security Optional IPsec Built-in support for IPsec
Configuration Manual/DHCP SLAAC, DHCPv6
IPv6 Address Example
Full IPv6 address:
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2001:0db8:85a3:0000:0000:8a2e:0370:7334
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Shortened IPv6 address:
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2001:db8:85a3::8a2e:370:7334
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IPv6 allows omission of leading zeros and consecutive groups of zeros.
Types of IPv6 Addresses
1. Unicast
Identifies a single device.
Example:
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2001:db8::1
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Similar to a home address.
2. Multicast
Sends data to multiple devices at once.
Example:
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ff02::1
`
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Similar to sending a message to a group chat.
3. Anycast
Multiple devices share the same address, and traffic is delivered to the nearest one.
Commonly used by DNS servers and content delivery networks.
Special IPv6 Addresses
Loopback Address
Equivalent to IPv4's 127.0.0.1
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::1
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Used to test networking on the local machine.
Example:
Shell
ping ::1
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Unspecified Address
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::
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Means "no address assigned."
Equivalent to IPv4:
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0.0.0.0
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Advantages of IPv6
✅ Vast number of addresses
✅ Better routing efficiency
✅ Auto-configuration (SLAAC)
✅ Improved multicast support
✅ End-to-end connectivity
✅ Better support for mobile devices
✅ Reduced need for NAT
IPv6 in a Home Network
Your ISP may assign an IPv6 address such as:
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2600:1700:abcd:1234::5
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Your computer, phone, game console, and smart TV can each receive their own public IPv6 address instead of sharing a single public IPv4 address through NAT.
Network+ Exam Tip
Remember these key IPv6 addresses:
Address Purpose::1 Loopback
:: Unspecified
fe80::/10 Link-local
fc00::/7 Unique local
ff00::/8 Multicast
2000::/3 Global unicast
Simple definition: IPv6 is a 128-bit addressing protocol that provides a much larger address space than IPv4 and is designed to support the future growth of the Internet.
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