Is an ipv4 address an ip address?

The ipv4 address is the ip address. IP address is a unified address format provided by the IP protocol and can be divided into two categories: 1. IPv4 address, which is the fourth revised version in the development process of the Internet Protocol and the first widely deployed version of this protocol; 2 , IPv6 address is the next-generation IP protocol designed by the Internet Engineering Task Force (IETF) to replace IPv4. Its number of addresses is claimed to be able to assign an address to every grain of sand in the world.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

IP address (Internet Protocol Address) refers to the Internet Protocol address, also translated as Internet Protocol address.

The IP address is a unified address format provided by the IP protocol. It assigns a logical address to each network and each host on the Internet to shield the differences in physical addresses.

There are two types of IP addresses now: ipv4 and IPv6.

Development History:

The first IP address that appeared was IPV4, which has only 4 segments of numbers, and the maximum number of each segment does not exceed 255. Due to the booming development of the Internet, the demand for IP addresses is increasing, making the issuance of IP addresses more stringent. Various data show that all global IPv4 addresses may be issued between 2005 and 2010 (the actual situation is that in 2019 The allocation of IPv4 addresses was completed on November 25, 2018). The lack of address space will definitely hinder the further development of the Internet. In order to expand the address space, it is planned to redefine the address space through IPv6. IPv6 uses a 128-bit address length. In the design process of IPv6, in addition to solving the address shortage problem once and for all, other problems that were not solved well in IPv4 were also considered.

The existing Internet runs on the basis of the IPv4 protocol. IPv6 is the next version of the Internet protocol, which can also be said to be the protocol of the next generation of Internet. It was originally proposed because with the rapid development of the Internet, the limited address space defined by IPv4 will be exhausted, and the shortage of address space will inevitably hinder the further development of the Internet. In order to expand the address space, it is planned to redefine the address space through IPv6. IPv4 uses a 32-bit address length, and there are only about 4.3 billion addresses, which are estimated to be allocated between 2005 and 2010, while IPv6 uses a 128-bit address length, which can provide almost unlimited addresses. According to a conservative estimate of the actual addresses that can be allocated to IPv6, more than 1,000 addresses can be allocated per square meter of the entire earth. In the design process of IPv6, in addition to solving the address shortage problem, other problems that were not solved well in IPv4 were also considered, mainly including end-to-end IP connection, quality of service (QoS), security, multicast, and mobility. , plug and play, etc.

With the rapid development of the Internet and the continuous improvement of Internet users' requirements for service levels, IPv6 will receive more and more attention around the world. In fact, there is no rush to promote IPv6. The problem of insufficient IPv4 addresses can be solved by simply extending 32 bits from 8 to 40 bits based on the existing IPv4. In this way, the number of available addresses is expanded by 256 times.

ipv4 address

Internet Protocol version 4 (English: Internet Protocol version 4, IPv4), also known as the fourth version of the Internet Communication Protocol, It is the fourth revision in the development process of the Internet Protocol and the first widely deployed version of this protocol. IPv4 is the core of the Internet and the most widely used version of the Internet Protocol. Its successor version is IPv6. Until 2011, when the IANA IPv4 addresses were completely exhausted, IPv6 was still in the early stages of deployment.

IPv4 is described in RFC 791 published by the IETF in September 1981, which replaced RFC 760 published in January 1980.

IPv4 is a connectionless protocol that operates on the link layer (such as Ethernet) using packet switching. This protocol delivers packets on a best-effort basis, meaning that it does not guarantee that any packet will reach its destination or that all packets will arrive in the correct order without duplication. These aspects are handled by upper-layer transport protocols (such as Transmission Control Protocol).

IPv4 uses 32-bit binary addresses, so there are only approximately 4.3 billion addresses. Initially, every user connected to the Internet must be assigned an IPv4 address, so there are fewer and fewer unallocated IPv4 addresses, resulting in the problem of IPv4 address exhaustion. In order to fundamentally solve the problem of IPv4 address exhaustion, IPv6 came into being.

IPv4 is usually written in dotted decimal notation, such as 192.168.0.1, where the numbers are all decimal numbers separated by solid dots.

An IPv4 address can be divided into two parts: the network address and the host address. The network address can be described in the following form: 192.168.0.0/16, where the number after the slash indicates that the length of the network address part is 16 bits. , which corresponds to 2 bytes, that is, the network address part is 192.168.0.0.

ipv6 address

IPv6 is the abbreviation of "Internet Protocol Version 6" in English and is the Internet Engineering Task Force The next generation IP protocol designed by (IETF) to replace IPv4, its number of addresses is claimed to be able to code an address for every grain of sand in the world.

The biggest problem of IPv4 is the insufficient network address resources, which seriously restricts the application and development of the Internet. The use of IPv6 can not only solve the problem of the number of network address resources, but also solve the obstacles for multiple access devices to connect to the Internet.

IPv6 is designed to replace IPv4. However, IPv4 has still occupied a dominant position in Internet traffic for a long time, and the use of IPv6 has grown slowly. In April 2022, the percentage of users using Google services through IPv6 exceeded 40% for the first time.

The IPv6 address length is 128 bits, which is 4 times the IPv4 address length. An IPv6 IP address consists of 8 address sections, each section contains 16 address bits, and the total length is 16x8=128 bits.

So the IPv4 dotted decimal format is no longer applicable and is expressed in hexadecimal.

IPv6 has 3 representation methods:

1. Hexadecimal representation

The format is X:X:X:X:X:X:X:X, where each X represents 16b in the address, expressed in hexadecimal, for example:

ABCD:EF01: 2345:6789:ABCD:EF01:2345:6789

In this notation, the leading 0 of each X can be omitted, for example:

2001:0DB8:0000:0023: 0008:0800:200C:417A→ 2001:DB8:0:23:8:800:200C:417A

2. 0-bit compressed representation

in a certain In some cases, an IPv6 address may contain a long period of 0s, and the continuous period of 0s can be compressed into "::". However, to ensure the uniqueness of address resolution, "::" can only appear once in the address, for example:

FF01:0:0:0:0:0:0:1101 → FF01::1101

0:0:0:0:0:0:0:1 → ::1

0:0:0:0:0:0:0:0 → ::

3. Embedded IPv4 address representation

In order to achieve IPv4-IPv6 interoperability, the IPv4 address will be embedded in the IPv6 address. At this time, the address is often expressed as: X:X:X ::X: Typical example, note that in the first 96b, the method of compressing 0 bits is still applicable

ipv6 address type

The IPv6 protocol mainly defines three There are three address types: Unicast Address (Unicast Address), Multicast Address (Multicast Address) and Anycast Address (Anycast Address). Compared with the original IPv4 address, a new "anycast address" type is added, and the broadcast address in the original IPv4 address is cancelled, because the broadcast function in IPv6 is completed through multicast.

Unicast address: Used to uniquely identify an interface, similar to the unicast address in IPv4. Datagrams sent to a unicast address will be delivered to an interface identified by this address.

Multicast address: used to identify a group of interfaces (usually this group of interfaces belong to different nodes), similar to the multicast address in IPv4. Datagrams sent to a multicast address are delivered to all interfaces identified by this address.

Anycast address: used to identify a group of interfaces (usually this group of interfaces belong to different nodes). Datagrams sent to an anycast address are delivered to the interface in the set of interfaces identified by this address that is closest to the source node (as measured by the routing protocol in use).

IPv6 address type is determined by the address prefix part. The correspondence between the main address types and address prefixes is as follows:

11111111FF00::/8

Address Type		Address Prefix (Binary)	IPv6 Prefix Identification
Unicast address	Unspecified address	00…0(128 bits)	::/128
	Loopback address	00…1(128 bits)	::1/128
	Link-local address	1111111010	FE80::/10
	Unique local address	1111 110	##FC00::/7 (including FD00::/8 and Uncommonly used FC00::/8)
	Site local address (deprecated, replaced by unique local address)	1111111011	FEC0::/10
	##Global Unicast Address	Other forms	-
##Multicast address
Anycast address	##Assigned from the unicast address space, using the unicast address Format

The difference between IPv4 and IPv6 protocols

1. Protocol The difference between addresses

1), address length

The IPv4 protocol has a 32-bit (4 bytes) address length; the IPv6 protocol has a 128-bit (16 bytes) address length

2), Address representation method

The IPv4 address is a binary number expressed as a decimal. IPv6 addresses are binary numbers represented in hexadecimal notation.

3) Address configuration

The IPv4 protocol address can be configured manually or through DHCP. [Recommended related video tutorials:

HTTP video tutorial

]

The IPv4 protocol requires the use of Internet Control Message Protocol version 6 (ICMPv6) or DHCPv6 Stateless Address Autoconfiguration (SLAAC).

2. Differences in data packets

1) Packet size

IPv4 protocol data packets require 576 bytes, fragmentation is optional . The IPv6 protocol data packet requires 1280 bytes and will not be fragmented

2), the header

The length of the IPv4 protocol header is 20 bytes, and does not recognize data for QoS processing Packet stream, including checksum, containing options field of up to 40 bytes.

The IPv6 protocol header is 40 bytes in length and contains the Flow Label field of the packet flow specified for QoS processing, excluding checksum; the IPv6 protocol has no field, but the IPv6 extension header is available.

3) Packet fragmentation

IPv4 protocol packet fragmentation will be completed by the forwarding router and the sending host. Packet fragmentation of the IPv6 protocol is only done by the sending host.

3. DNS record

IPv4 protocol address (A) record, mapping host name; pointer (PTR) record, IN-ADDR.ARPA DNS domain.

IPv6 protocol address (AAAA) record, mapped host name; pointer (PTR) record, IP6.ARPA DNS domain

4, IPSec support

IPSec support for the IPv4 protocol is only optional. The IPv4 protocol has built-in IPSec support.

5. Address Resolution Protocol

IPv4 Protocol: Address Resolution Protocol (ARP) can be used to map IPv4 addresses to MAC addresses.

IPv6 protocol: Address Resolution Protocol (ARP) is replaced by the functionality of Neighbor Discovery Protocol (NDP).

6. Authentication and encryption

Pv6 provides authentication and encryption, but IPv4 does not.

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