ipaddress.txe

An introduction to the ipaddress module
***************************************

author:
   Peter Moody

author:
   Nick Coghlan

Overview
^^^^^^^^

This document aims to provide a gentle introduction to the "ipaddress"
module. It is aimed primarily at users that aren't already familiar
with IP networking terminology（术语）, but may also be useful to network
engineers wanting an overview（概述） of how "ipaddress" represents IP network
addressing concepts.
 aims to 旨意
本文旨在对“ipaddress”进行温和介绍
模块。 它主要针对尚不熟悉的用户
使用IP网络术语，但也可能对网络有用
工程师想要概述“ipaddress”如何代表IP网络
解决概念。

Creating Address/Network/Interface objects
==========================================

Since "ipaddress" is a module for inspecting（检查） and manipulating（操作） IP
addresses, the first thing you'll want to do is create some objects.
You can use "ipaddress" to create objects from strings and integers（）.

A Note on IP Versions  关于ip版本的说明
---------------------

For readers that aren't particularly（不怎么，不见得） familiar with IP addressing, it's
important to know that the Internet Protocol is currently（当前） in the
process（过程） of moving from version 4 of the protocol to version 6. This
transition（过度，转变） is occurring（发生） largely because version 4 of the protocol
doesn't provide enough addresses to handle the needs of the whole
world, especially given the increasing number of devices（设备，器件） with direct（直接）
connections to the internet.

Explaining（解释） the details（细节） of the differences between the two versions of
the protocol is beyond the scope（视野范围） of this introduction, but readers
need to at least be aware that these two versions exist, and it will
sometimes be necessary to force the use of one version or the other.
force 推动，促使

IP Host Addresses  ip主机地址 
-----------------

Addresses, often referred to as "host addresses" are the most basic
unit when working with IP addressing. The simplest way to create
addresses is to use the "ipaddress.ip_address()" factory function,
which automatically（自动的） determines（决心，确定） whether to create an IPv4 or IPv6
address based on the passed（通过） in value:

 referred to as 被称为
 referred  参考，提到

>>> ipaddress.ip_address('192.0.2.1')
IPv4Address('192.0.2.1')
>>> ipaddress.ip_address('2001:DB8::1')
IPv6Address('2001:db8::1')

Addresses can also be created directly from integers. Values that will
fit（适合） within（在...之内） 32 bits are assumed to be IPv4 addresses:
are assumed to 假设为

   >>> ipaddress.ip_address(3221225985)
   IPv4Address('192.0.2.1')
   >>> ipaddress.ip_address(42540766411282592856903984951653826561)
   IPv6Address('2001:db8::1')

To force（促使） the use of IPv4 or IPv6 addresses, the relevant（相关的，有关的） classes can
be invoked（调用） directly. This is particularly（特别的，尤其的） useful to force creation of
IPv6 addresses for small integers:

   >>> ipaddress.ip_address(1)
   IPv4Address('0.0.0.1')
   >>> ipaddress.IPv4Address(1)
   IPv4Address('0.0.0.1')
   >>> ipaddress.IPv6Address(1)
   IPv6Address('::1')

Defining Networks（网络）
-----------------

Host addresses are usually grouped together（grouped together 集合在一起） into IP networks, so
"ipaddress" provides a way to create, inspect and manipulate network
definitions. IP network objects are constructed from strings that
define the range（范围，幅度） of host addresses that are part of that network. The
simplest form for that information is a "network address/network
prefix（前缀）" pair（一对）， where the prefix defines the number of leading bits that
are compared to determine whether or not an address is part of the
network and the network address defines the expected value of those
bits.

主机地址通常组合在一起（组合在一起在一起）到IP网络，所以
“ipaddress”提供了一种创建，检查和操作网络的方法
定义。 IP网络对象由字符串构成
定义属于该网络的主机地址的范围（范围，幅度）。该
该信息的最简单形式是“网络地址/网络
prefix（前缀）“pair（一对），其中前缀定义前导位数
比较以确定地址是否是其中的一部分
网络和网络地址定义了那些的预期值
位。
As for addresses, a factory function is provided that determines the
correct IP version automatically:
as for 关于，至于

   >>> ipaddress.ip_network('192.0.2.0/24')
   IPv4Network('192.0.2.0/24')
   >>> ipaddress.ip_network('2001:db8::0/96')
   IPv6Network('2001:db8::/96')

Network objects cannot have any host bits set.  The practical effect
of this is that "192.0.2.1/24" does not describe a network.  Such
definitions are referred to as interface objects since the ip-
on-a-network notation is commonly used to describe network interfaces
of a computer on a given network and are described further in the next
section.
网络对象不能设置任何主机位。 实际效果
这是“192.0.2.1/24”没有描述网络。 这样
自从ip-以来，定义被称为接口对象
网络上的表示法通常用于描述网络接口
在给定网络上的计算机，并在下面进一步描述
部分。

By default, attempting to create a network object with host bits set
will result in "ValueError" being raised. To request that the
additional bits instead be coerced to zero, the flag "strict=False"
can be passed to the constructor:
默认情况下，尝试创建具有主机位设置的网络对象
将导致“ValueError”被引发。 要求那个
附加位反而被强制为零，标志“strict = False”
可以传递给构造函数：

   >>> ipaddress.ip_network('192.0.2.1/24')
   Traceback (most recent call last):
      ...
   ValueError: 192.0.2.1/24 has host bits set
   >>> ipaddress.ip_network('192.0.2.1/24', strict=False)
   IPv4Network('192.0.2.0/24')

While the string form offers significantly more flexibility, networks
can also be defined with integers, just like host addresses. In this
case, the network is considered to contain only the single address
identified by the integer, so the network prefix includes the entire
network address:
虽然字符串形式提供了更大的灵活性，网络
也可以用整数定义，就像主机地址一样。 在这
在这种情况下，网络被认为只包含单个地址
由整数标识，因此网络前缀包括整个
网络地址：

   >>> ipaddress.ip_network(3221225984)
   IPv4Network('192.0.2.0/32')
   >>> ipaddress.ip_network(42540766411282592856903984951653826560)
   IPv6Network('2001:db8::/128')

As with addresses, creation of a particular kind of network can be
forced by calling the class constructor directly instead of using the
factory function.
与地址一样，可以创建特定类型的网络
通过直接调用类构造函数而不是使用
工厂功能。

Host Interfaces 主机接口
---------------

As mentioned just above, if you need to describe an address on a
particular network, neither the address nor the network classes are
sufficient（足够的，充分的）. Notation like "192.0.2.1/24" is commonlyt(通常) used by network
engineers and the people who write tools for firewalls and routers as
shorthand for "the host "192.0.2.1" on the network "192.0.2.0/24"",
Accordingly, "ipaddress" provides a set of hybrid classes that
associate an address with a particular network. The interface for
creation is identical to that for defining network objects, except
that the address portion isn't constrained to being a network address.
如上所述，如果您需要描述一个地址
特定网络，地址和网络类都不是
足够。 网络通常使用“192.0.2.1/24”之类的符号
工程师和为防火墙和路由器编写工具的人
“主机”192.0.2.1“在网络上”192.0.2.0/24“”的简写，
因此，“ipaddress”提供了一组混合类
将地址与特定网络相关联。 接口为
创建与定义网络对象的创建相同，除外
地址部分不限于网络地址。

>>> ipaddress.ip_interface('192.0.2.1/24')
IPv4Interface('192.0.2.1/24')
>>> ipaddress.ip_interface('2001:db8::1/96')
IPv6Interface('2001:db8::1/96')

Integer inputs are accepted (as with networks), and use of a
particular IP version can be forced by calling the relevant
constructor directly.

Inspecting Address/Network/Interface Objects
============================================

You've gone to the trouble of creating an
IPv(4|6)(Address|Network|Interface) object, so you probably want to
get information about it.  "ipaddress" tries to make doing this easy
and intuitive.

Extracting the IP version:

   >>> addr4 = ipaddress.ip_address('192.0.2.1')
   >>> addr6 = ipaddress.ip_address('2001:db8::1')
   >>> addr6.version
   6
   >>> addr4.version
   4

Obtaining the network from an interface:

   >>> host4 = ipaddress.ip_interface('192.0.2.1/24')
   >>> host4.network
   IPv4Network('192.0.2.0/24')
   >>> host6 = ipaddress.ip_interface('2001:db8::1/96')
   >>> host6.network
   IPv6Network('2001:db8::/96')

Finding out how many individual addresses are in a network:

   >>> net4 = ipaddress.ip_network('192.0.2.0/24')
   >>> net4.num_addresses
   256
   >>> net6 = ipaddress.ip_network('2001:db8::0/96')
   >>> net6.num_addresses
   4294967296

Iterating through the "usable" addresses on a network:

   >>> net4 = ipaddress.ip_network('192.0.2.0/24')
   >>> for x in net4.hosts():
   ...     print(x)  # doctest: +ELLIPSIS
   192.0.2.1
   192.0.2.2
   192.0.2.3
   192.0.2.4
   ...
   192.0.2.252
   192.0.2.253
   192.0.2.254

Obtaining the netmask (i.e. set bits corresponding to the network
prefix) or the hostmask (any bits that are not part of the netmask):
获得网络掩码（即设置对应于网络的位）
前缀）或主机掩码（不属于网络掩码的任何位）：

>>> net4 = ipaddress.ip_network('192.0.2.0/24')
>>> net4.netmask
IPv4Address('255.255.255.0')
>>> net4.hostmask
IPv4Address('0.0.0.255')
>>> net6 = ipaddress.ip_network('2001:db8::0/96')
>>> net6.netmask
IPv6Address('ffff:ffff:ffff:ffff:ffff:ffff::')
>>> net6.hostmask
IPv6Address('::ffff:ffff')

Exploding or compressing the address:

   >>> addr6.exploded
   '2001:0db8:0000:0000:0000:0000:0000:0001'
   >>> addr6.compressed
   '2001:db8::1'
   >>> net6.exploded
   '2001:0db8:0000:0000:0000:0000:0000:0000/96'
   >>> net6.compressed
   '2001:db8::/96'

While IPv4 doesn't support explosion or compression, the associated
objects still provide the relevant properties so that version neutral
code can easily ensure the most concise or most verbose form is used
for IPv6 addresses while still correctly handling IPv4 addresses.

而IPv4不支持爆炸或压缩，相关联
对象仍然提供相关属性，以便版本中立
代码可以轻松确保使用最简洁或最详细的表单
用于IPv6地址，同时仍能正确处理IPv4地址。

Networks as lists of Addresses 网络作为地址列表
==============================

It's sometimes useful to treat networks as lists.  This means it is
possible to index them like this:
将网络视为列表有时很有用。 这意味着它
可以像这样索引它们：

   >>> net4[1]
   IPv4Address('192.0.2.1')
   >>> net4[-1]
   IPv4Address('192.0.2.255')
   >>> net6[1]
   IPv6Address('2001:db8::1')
   >>> net6[-1]
   IPv6Address('2001:db8::ffff:ffff')

It also means that network objects lend themselves to using the list
membership test syntax like this:
它还意味着网络对象适合使用列表
成员资格测试语法如下：

   if address in network:
       # do something

Containment testing is done efficiently based on the network prefix:

   >>> addr4 = ipaddress.ip_address('192.0.2.1')
   >>> addr4 in ipaddress.ip_network('192.0.2.0/24')
   True
   >>> addr4 in ipaddress.ip_network('192.0.3.0/24')
   False

Comparisons
===========

"ipaddress" provides some simple, hopefully intuitive ways to compare
objects, where it makes sense:

   >>> ipaddress.ip_address('192.0.2.1') < ipaddress.ip_address('192.0.2.2')
   True

A "TypeError" exception is raised if you try to compare objects of
different versions or different types.

Using IP Addresses with other modules
=====================================

Other modules that use IP addresses (such as "socket") usually won't
accept objects from this module directly. Instead, they must be
coerced to an integer or string that the other module will accept:

   >>> addr4 = ipaddress.ip_address('192.0.2.1')
   >>> str(addr4)
   '192.0.2.1'
   >>> int(addr4)
   3221225985

Getting more detail when instance creation fails
================================================

When creating address/network/interface objects using the version-
agnostic factory functions, any errors will be reported as
"ValueError" with a generic error message that simply says the passed
in value was not recognized as an object of that type. The lack of a
specific error is because it's necessary to know whether the value is
*supposed* to be IPv4 or IPv6 in order to provide more detail on why
it has been rejected.

To support use cases where it is useful to have access to this
additional detail, the individual class constructors actually raise
the "ValueError" subclasses "ipaddress.AddressValueError" and
"ipaddress.NetmaskValueError" to indicate exactly which part of the
definition failed to parse correctly.

The error messages are significantly more detailed when using the
class constructors directly. For example:

   >>> ipaddress.ip_address("192.168.0.256")
   Traceback (most recent call last):
     ...
   ValueError: '192.168.0.256' does not appear to be an IPv4 or IPv6 address
   >>> ipaddress.IPv4Address("192.168.0.256")
   Traceback (most recent call last):
     ...
   ipaddress.AddressValueError: Octet 256 (> 255) not permitted in '192.168.0.256'

   >>> ipaddress.ip_network("192.168.0.1/64")
   Traceback (most recent call last):
     ...
   ValueError: '192.168.0.1/64' does not appear to be an IPv4 or IPv6 network
   >>> ipaddress.IPv4Network("192.168.0.1/64")
   Traceback (most recent call last):
     ...
   ipaddress.NetmaskValueError: '64' is not a valid netmask

However, both of the module specific exceptions have "ValueError" as
their parent class, so if you're not concerned with the particular
type of error, you can still write code like the following:

   try:
       network = ipaddress.IPv4Network(address)
   except ValueError:
       print('address/netmask is invalid for IPv4:', address)