10 things you need to know about IPV6

In the past few years, IPV6 has gradually become mainstream, but many IT professionals in the face of IPv6, indeed, IPv6 and IPv4 are very different, this article to write, hoping to help you eliminate IPV6 phobia.

1, IPV6 address is a 128-digit hexadecimal number

The IPV4 address is composed of 4 numeric bit groups (32 bits in total), 128 bits at the length of the IPV6 address, and 16 characters. In IPv4, each bit group is made up of 0-255 decimal digits, which are separated by a period of English, and IPV6 addresses are composed of 8 groups, each of which consists of 16 digits of 4 characters.

2, it is easy to identify link-local unicast address

IPV6 reserved special address headers for different address types, the most obvious example being that a link-local unicast address starts with a PE80, and the multicast address starts with ff0x, where x is a placeholder and can be replaced with the number 1-8.

3. Support address abbreviation

Because IPv6 's address is longer, it often contains a lot of 0, and if a bit group has 0 characters, these 0 can be abbreviated to a 0, for example, the following address:

fe80:cd00:0000:0cde:1257:0000:211e:729c

can be abbreviated as

fe80:cd00:0:cde:1257:0:211e:729c

4, can omit the continuous 0

If the characters of consecutive multiple bit groups are all 0, you can omit all 0, for example, the following address:

fe80:cd00:0000:0000:0000:0000:211e:729c

In addition to the method introduced in the 3rd, the abbreviation can also be omitted directly from the continuous 0, with two English colon instead, the operating system to see such a IPv6 address, nature will know that the word between them Fu Quan is 0. So the address above can be abbreviated as

fe80:cd00::211e:729c

5, IPv6 of the ring back address

In IPv4, we know that the loopback address is a special address to this machine, that is, our familiar 127.0.0.1,ipv6 is no exception, also designed the loopback address, as follows:

0000:0000:0000:0000:0000:0000:0000:0001

Refer to the ellipsis of the 4th article, IPV6 's loopback address becomes

:: 1

Does this look like a valid IP address?

6, do not need the traditional subnet mask

In IPv4, each IP address must be paired with a subnet mask to use, IPV6 also uses the concept of a subnet, but the subnet ID is embedded directly in the address. In IPv6, the first 48 digits represent the network prefix, followed by the 16-bit subnet ID, and the last 64 bits are the interface IDs, the interface ID or the device ID. BITS reserved for device IDs can be borrowed to represent additional subnet masks, if needed, but are usually unwanted because 16-bit subnets and 64-bit device IDs can provide up to 65,536 subnets.

7, IPv6 still need DNS

In IPv4, host records (that is, a record) map IP addresses to host names, IPV6 still use DNS technology, but IPV6 no longer use host records, instead, IPv6 use AAAA resource records, ip6.arpa for reverse host name resolution.

8. IPV6 Tunnel communication can be realized across IPV4 network

One reason for the delay in IPV6 is that it is not fully compatible with IPV4, so there are tunneling technologies that walk IPV6 communications on IPV4 Networks, one is Teredo and the other is 6to4, although their working methods are somewhat different, But the basic idea is to encapsulate IPV6 packets into IPV4 packets for transmission, but both ends of communication require the ability to package and reconcile.

9, you may already be using IPV6.

Starting with Windows Vista, Microsoft has installed the IPV6 driver by default, and the IPV6 protocol is enabled by default, because all of this is automatically configured, you may not know it, but only operating system support IPV6 is not enough, all switches and routers must support, in addition, There are also poorly designed applications that hard-code IPV4 addresses into programs that are stumbling blocks to IPv6 popularity.

10. Windows does not fully support IPV6

Although Microsoft has been very active in supporting IPV6, Windows does not fully support IPV6, for example, in Windows, we used to access network shared folders (such as//127.0.0.1/c$) using UNC (Universal Naming convention). But now you can't use IPV6 to do this, because when Windows sees a colon in a IPv6 address, it treats it as a drive letter.

To solve this problem, Microsoft has created a special domain for IPV6 address conversion, and if you use the IPV6 address in a UNC path, you must use a dash instead of a colon and add the. ipv6.literal.net suffix at the end of the address, for example fe80-ab00– 200d-617b.ipv6.literal.net.

Turn from: http://www.oschina.net/bbs/thread/13034
This article is the use of B3log Solo from the simple design of the art of the synchronization of the release of the original address: http://88250.b3log.org/articles/2010/11/17/1290007783671.html