Ten Facts About IPv6 Addresses
We offer ten interesting facts about the new IPv6 data transfer protocol.
1. IPv6 addresses are 128-bit hexadecimal numbers.
Standard IPv4 addresses consist of four groups of eight digits. Together, these groups form a 32-bit number. The groups of digits in these addresses are decimal numbers from 0 to 255 and are separated by periods.
The new IPv6 addresses are 128-bit hexadecimal numbers. IPv6 addresses are composed of eight groups of four hexadecimal digits each. Each group is 16 bits long, and together they form a 128-bit address. In certain cases, IPv6 addresses can be abbreviated for ease of notation.
2. Unicast link-local addresses are easy to identify
The IPv6 protocol allows for specific opening characters for different types of addresses. For example, link-local unicast addresses always begin with "FE80." Multicast addresses begin with "FF0x," where "x" is a number from 1 to 8.
3. Zeros at the beginning of a group of numbers are hidden
Because IPv6 addresses are very long, they typically contain many zeros. One or more zeros that begin an address segment are simply placeholders and may therefore be hidden.
4. Zeros in the middle of a group of numbers can also sometimes be hidden
IPv6 addresses typically have several segments consisting entirely of zeros, which can also be suppressed. To avoid suppressing leading zeros in each segment, you can eliminate all consecutive zeros and replace them with two colons. Two colons in an address mean that all segments between them are composed entirely of zeros.
But only segments consisting entirely of zeros can be eliminated. And a double colon can only be used once in an address.
5. The loopback address doesn't even look like an address
The IPv4 protocol assigns a specific loopback address to the local computer: 127.0.0.1. IPv6 also has this address: 0000:0000:0000:0000:0000:0000:0000:0001. However, after removing all unnecessary zeros, it no longer even resembles an address and is usually written as ::1.
6. Traditional subnet masks are not needed for IPv6
Every IPv4 address has a subnet mask. In IPv6 protocols, the subnet identifier is included directly in the address.
The first 48 bits are the network prefix, and the next 16 bits are the subnet ID. The last 64 bits are the interface (or device) ID.
7. DNS is still in use
The IPv4 protocol uses the A record to bind a hostname to an IP address. IPv6 also uses DNS, but uses AAAA resource records for binding. The domain ip6.arpa is used for reverse hostname resolution.
8. IPv6 can be tunneled over IPv4 networks
One of the reasons IPv6 is not yet popular is its incompatibility with IPv4 networks. Various tunneling technologies are used to address this issue, including Teredo and 6to4. These technologies operate differently, but both involve encapsulating IPv6 packets within IPv4 packets to allow IPv6 traffic to pass over IPv4 networks. However, for this technique to be successful, both ends of the tunnel must have tunnel endpoints to retrieve the encapsulated IPv6 packets.
9. You may already be using IPv6
Starting with Windows Vista, Microsoft has enabled IPv6 support in its operating systems by default. However, not all switches and routers support IPv6, and many applications have built-in references to IPv4 addresses.
10. Windows does not provide full IPv6 support
Although Microsoft is actively promoting IPv6, Windows doesn't yet fully support the new protocol. For example, an IPv4 address can be included in the full name of a network resource—for example, \\127.0.0.1\C$. However, this isn't possible with an IPv6 address, because the system recognizes the colon as a drive letter.
To address this issue, Microsoft created a domain for IPv6 address translation. To include this address in a file path formatted according to the Universal Naming Convention (UNC), replace colons with hyphens and append ".ipv6.literal.net" to the end of the address—for example, FE80-AB00–200D-617B.ipv6.literal.net.
