什么是 IP 地址：基本概念和技术细节 (什么是ip地址,举例说明)

IP (Internet Protocol，互联网协议) 地址是唯一标识互联网上连接到网络设备的数字标签。它就像设备在网络上的邮寄地址，允许数据在不同设备之间传输。

IP 地址的组成

IP 地址由四个 8 位字节组成，用点 (.) 分隔。每个字节表示一个数字（0-255）。IP 地址通常表示为如 "192.168.1.1" 的格式。

32 位 IPv4 地址

最常见的 IP 地址类型是 IPv4，使用 32 位地址空间。以十进制表示时，IP 地址范围为 0.0.0.0 至 255.255.255.255。

128 位 IPv6 地址

IPv6 是更新版本的 IP 协议，使用 128 位地址空间。IPv6 地址用八个 16 位十六进制数字表示，用冒号 (:) 分隔。例如："2001:0db8:85a3:08d3:1319:8a2e:0370:7334"。

IP 地址类别

IP 地址根据其网络位置和网络规模分为不同的类别：

什么是IP地址

IP地址称作网络协议地址，是分配给主机的一个32位地址，由4个字节组成，分为动态IP地址和静态IP地址两种。接下来我为大家整理了什么是IP地址，希望对你有帮助哦!

IP地址(Internet Protocol Address)是一种在Internet上的给主机编址的方式，也称为网际协议地址。由32位二进制数组成，为便于使用，常以形式表现，每组XXX代表小于等于255的10进制数。例如202.96.155.9。Internet中，IP地址是唯一的。目前IP技术可能使用的IP地址最多可有约42亿个。骤看可能觉得很难会用尽，但由于早期编码上的问题，使很多编码实际上被丢空或不能使用。加上因特网的普及，使每个家庭都至少有一部电脑，连同公司的电脑，以及连接每个网络的服务器，长此下去，专家担心随着Internet的发展，将不够用。所以相应的科研组织正在研究128位的IP地址，其IP地址数量最高可达 3. × 1038 个，地球上的每一粒沙子都可以拥有自己的IP地址，这种新版的IP地址技术叫IPv6。

An IP address (Internet Protocol address) is a unique number that devices use in order to identify and communicate with each other on a network utilizing the Internet Protocol standard. Any participating device — including routers, computers, time-servers, internet FAX machines, and some telephones — must have its own unique address. This allows information passed onwards on behalf of the sender to indicate where to send it next, and for the receiver of the information to know that it is the intended destination.

The numbers currently used in IP addresses range from 1.0.0.0 to 255.255.255.255, though some of these values are reserved for specific purposes. This does not provide enough possibilities for every internet device to have its own permanent number. Subnet routing, Network Address Translation and the Dynamic Host Configuration Protocol (DHCP) server all allow local networks to use the same IP addresses as other networks elsewhere though both are connected to the Internet. Devices such as network printers, web servers and email servers are often allocated static IP addresses so they can always be found.

IP addresses are conceptually similar to phone numbers, except they are used in LANs (Local Area Network), WANs (Wide Area Network), or the Internet. Because the numbers are not easy for humans to remember, the Domain Name System provides a service analogous to an address book lookup called domain name resolution or name resolution. Special DNS servers on the internet are dedicated to performing the translation from a domain name to an IP address and vice versa.

More detail

The Internet Protocol (IP) knows each logical host interface by a number, the IP address. On any given network, this number must be unique among all the host interfaces that communicate through this network. Users of the Internet are sometimes given a host name in addition to their numerical IP address by their Internet service provider.

The IP addresses of users browsing the World Wide Web are used to enable communications with the server of the Web site. Also, it is usually in the header of email messages one sends. In fact, for all programs that utilize the TCP/IP protocol, the sender IP address and destination IP address are required in order to establish communications and send highlight=true> currently has the number , written as 207.142.131.236 in base-256: equals 207×2563 142×2562 131×2561 236×2560. (Resolving the name to its associated number is handled by Domain Name System servers.)

IPv4 addresses were originally divided into two parts: the network and the host. A later change increased that to three parts: the network, the subnetwork, and the host, in that order. However, with the advent of classless inter-domain routing (CIDR), this distinction is no longer meaningful, and the address can have an arbitrary number of levels of hierarchy. (Technically, this was already true any time after the advent of subnets, since a site could elect to have more than one level of subnetting inside a network number.)

Assignment

Each interface of a device is assigned, at least theoretically, a unique IP address. In practice, some interfaces may be unnumbered, and many addresses are not globally unique.

The actual assignment of an address is not arbitrary. The fundamental principle of routing, that addresses encode information about a devices location within a network, implies that an address assigned to one part of a network will not function in another part of the network. A hierarchical structure, standardized by CIDR and overseen by the Internet Assigned Numbers Authority (IANA) and its Regional Internet Registries (RIRs), manages the assignment of Internet address worldwide. Each RIR maintains a publically searchable WHOIS database that provides information about IP address assignments; information from these databases plays a central role in numerous tools which attempt to locate IP addresses geographically.

Exhaustion

Some private IP address space has been allocated via RFC 1918. This means the addresses are available for any use by anyone and therefore the same RFC 1918 IP addresses can be reused. However they are not routable on the Internet. They are used extensively due to the shortage of registerable addresses. Network address translation (NAT) is required to connect those networks to the Internet.

While a number of measures have been taken to conserve the limited existing IPv4 address space (such as the use of NAT and Private Addressing), the number of 32-bit IP addresses is not sufficient to accommodate the long-term growth of the Internet. For this reason, the plan is that the Internet 128-bit IPv6 addressing scheme will be adopted over the next 5 to 15 years.

IP version 5

What would be considered IPv5 existed only as an experimental non-IP real time streaming protocol called ST2, described in RFC 1819. In keeping with standard UNIX release conventions, all odd-numbered versions are considered experimental, and this version was never intended to be implemented; the protocol was not abandoned. RSVP has replaced it to some degree.

IP version 6

In IPv6, the new (but not yet widely deployed) standard protocol for the Internet, addresses are 128 bits wide, which, even with generous assignment of netblocks, should suffice for the foreseeable future. In theory, there would be exactly 2128, or about 3.403 × 1038 unique host interface addresses. If the earth were made entirely out of 1 cubic millimeter grains of sand, then you could give a unique address to each grain in 300 million planets the size of the earth. This large address space will be sparsely populated, which makes it possible to again encode more routing information into the addresses themselves.

Addressing

A version 6 address is written as eight 4-digit hexadecimal numbers separated by colons. For readability, addresses may be shortened in two ways. Within each colon-delimited section, leading zeroes may be truncated. Secondly, one string of zeroes (and only one) may be replaced with two colons (::). For example, all of the following addresses are equivalent:

1080:0000:0000:0000:0000:0034:0000:417A

1080:0:0:0:0:34:0:417A

1080::34:0:417A

Global unicast IPv6 addresses are constructed as two parts: a 64-bit routing part followed by a 64-bit host identifier.

Netblocks are specified as in the modern alternative for IPv4: network number, followed by a slash, and the number of relevant bits of the network number (in decimal). Example: 12AB::CD30:0:0:0:0/60 includes all addresses starting with 12ABCD3.

IPv6 has many improvements over IPv4 other than just bigger address space, including autorenumbering and mandatory support for IPsec.

ip地址是什么意思

大多数计算机网络，包括互联网，均使用传输控制协议/网际协议(TCP/IP)来启动网络连接设备和计算机之间的网络通信。这是两个不同的，独立的协议，但是通常一起使用，而且TCP/IP是对协议进行描述的实际标准。

让我们深入了解一下TCP/IP的功能。这共计有四层，且每一层都有自己的一套协议。它们分别是：

数据链路层由仅能作用于链接的协议和方法组成。从网络层面来说，链接所连接的是网络上的主机或节点。以太网是运行于数据链路层中的一个协议示例。

网络层用于连接网络，同时跨越网络边界传输数据包。网际协议(IP)和网络控制报文协议(ICMP)用于本层。

下一层是传输层。它控制的是主机之间的通信。传输控制协议(TCP)和用户数据报协议(UDP)是可能用于本层的两大协议。

应用层由很多协议组成，包括文件传输协议(FTP)，简单邮件传输协议(SMTP)，和超文本传输协议(HTTP)。本层负责对应用交换程序的方式进行标准化处理。

所以TCP/IP这个缩略词来自于上述其中两层所使用的协议。

TCP是将文件或传输数据分解成网际之间传送的数据包的元素。它还会在数据包抵达目的地时对其进行重组。

IP对每一数据包的地址予以控制。这些地址确保了相关数据得以发送至正确的目的地。

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开始使用IP地址之间的不同

IP地址有一系列不同的形式。区分IP地址主要的不同特点如下。

IPv4和IPv6

目前用于位置寻址和身份确认的IP主要有两大版本。

IPv4使用32位地址，表现为十进制形式。您可能会对看起来像是这样的IP地址非常熟悉：

196.243.122.3.

这种IP形式在数量上存在限制，也即只有4,294,967,296个IP地址可以使用IPv4协议。

IPv6使用128位地址，其所额外带来的IP地址数量呈指数型增长，它可以创造的IP地址的数量为340,282,366,920,938,463,463,374,607,431,768,211,456个。此类IP地址表现为十六进制形式：

2001:0db8:85a3:0000:0000:8a2e:0370:7334.

IPv6应运而生的主要原因在于IPv4无法为世界范围内的所有网络连接设备提供充足的IP地址。尽管它们无法直接实现对接，但是这两种协议可以一起运行。

动态和静态

当您连接到互联网时，还有两大类IP地址之间存在显著的不同。静态IP地址在各个网络连接之间不会发生变化。您的家庭网络连接可能是一个与您的路由器绑定的静态IP。动态IP地址是在您连接网络时由您的网络服务供应商分配的，它可能会随着时间的变化而发生改变。

静态IP对于部分企业来说可能具有一定的优势，但是归根结底，IP地址只是用于网络的连接，任何一种类型的IP地址均可实现此目的。

IP地址是什么意思？

IP地址是指互联网协议地址，是IP协议提供的一种统一的地址格式，为互联网上的每一个网络和每一台主机分配一个逻辑地址，以此来屏蔽物理地址的差异。