公用ip地址查询_是什么使您无法更改公用IP地址并在Internet上造成严重破坏？

公用ip地址查询

What exactly is preventing you (or anyone else) from changing their IP address and causing all sorts of headaches for ISPs and other Internet users?

到底是什么在阻止您(或其他任何人)更改其IP地址并导致ISP和其他Internet用户感到头疼？

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

今天的“问答”环节由SuperUser提供，它是Stack Exchange的一个分支，该社区是由社区驱动的Q＆A网站分组。

问题 (The Question)

SuperUser reader Whitemage is curious about what’s preventing him from wantonly changing his IP address and causing trouble:

超级用户读者Whitemage很好奇为什么阻止他大肆更改IP地址并造成麻烦：

An interesting question was asked of me and I did not know what to answer. So I’ll ask here.

问了一个有趣的问题，我不知道该怎么回答。所以我会在这里问。

Let’s say I subscribed to an ISP and I’m using cable internet access. The ISP gives me a public IP address of 60.61.62.63.

假设我订阅了ISP，并且正在使用有线互联网访问。 ISP给了我一个公共IP地址60.61.62.63。

What keeps me from changing this IP address to, let’s say, 60.61.62.75, and messing with another consumer’s internet access?

是什么让我无法将此IP地址更改为60.61.62.75，并弄乱了另一个消费者的互联网访问权限？

For the sake of this argument, let’s say that this other IP address is also owned by the same ISP. Also, let’s assume that it’s possible for me to go into the cable modem settings and manually change the IP address.

为了这个论点，假设另一个IP地址也由同一ISP拥有。另外，假设我可以进入电缆调制解调器设置并手动更改IP地址。

Under a business contract where you are allocated static addresses, you are also assigned a default gateway, a network address and a broadcast address. So that’s 3 addresses the ISP “loses” to you. That seems very wasteful for dynamically assigned IP addresses, which the majority of customers are.

在为您分配了静态地址的商业合同下，还为您分配了默认网关，网络地址和广播地址。这样就可以解决ISP向您“丢失”的3个问题。对于大多数客户都是动态分配的IP地址，这似乎非常浪费。

Could they simply be using static arps? ACLs? Other simple mechanisms?
他们可以简单地使用静态arps吗？ ACL？其他简单的机制？

Two things to investigate here, why can’t we just go around changing our addresses, and is the assignment process as wasteful as it seems?

这里有两件事情需要调查，为什么我们不能只是四处更改地址，分配过程看起来是否很浪费？

答案 (The Answer)

SuperUser contributor Moses offers some insight:

超级用户贡献者Moses提供了一些见解：

Cable modems aren’t like your home router (ie. they don’t have a web interface with simple point-and-click buttons that any kid can “hack” into).

电缆调制解调器不像您的家用路由器(即，它们不具有带有简单的点击按钮的Web界面，任何孩子都可以“点击”)。

Cable modems are “looked up” and located by their MAC address by the ISP, and are typically accessed by technicians using proprietary software that only they have access to, that only runs on their servers, and therefore can’t really be stolen.

ISP会“查找”电缆调制解调器并按其MAC地址定位电缆调制解调器，技术人员通常使用专有软件访问它们，这些专有软件只有他们可以访问，只能在其服务器上运行，因此实际上无法被盗。

Cable modems also authenticate and cross-check settings with the ISPs servers. The server has to tell the modem whether it’s settings (and location on the cable network) are valid, and simply sets it to what the ISP has it set it for (bandwidth, DHCP allocations, etc). For instance, when you tell your ISP “I would like a static IP, please.”, they allocate one to the modem through their servers, and the modem allows you to use that IP. Same with bandwidth changes, for instance.

电缆调制解调器还通过ISP服务器验证和交叉检查设置。服务器必须告诉调制解调器其设置(和电缆网络上的位置)是否有效，并且只需将其设置为ISP为其设置的设置(带宽，DHCP分配等)即可。例如，当您告诉您的ISP“请给我一个静态IP。”时，他们通过服务器将一个IP分配给调制解调器，而调制解调器则允许您使用该IP。例如，与带宽更改相同。

To do what you are suggesting, you would likely have to break into the servers at the ISP and change what it has set up for your modem.

要执行您的建议，您可能必须闯入ISP的服务器并更改为调制解调器设置的内容。

Could they simply be using static arps? ACLs? Other simple mechanisms?

他们可以简单地使用静态arps吗？ ACL？ 其他简单的机制？

Every ISP is different, both in practice and how close they are with the larger network that is providing service to them. Depending on those factors, they could be using a combination of ACL and static ARP. It also depends on the technology in the cable network itself. The ISP I worked for used some form of ACL, but that knowledge was a little beyond my paygrade. I only got to work with the technician’s interface and do routine maintenance and service changes.

每个ISP在实践上以及与提供服务的较大网络之间的距离都不同。根据这些因素，他们可能会结合使用ACL和静态ARP。它还取决于电缆网络本身的技术。我曾经工作过的ISP使用了某种形式的ACL，但是这些知识超出了我的薪水范围。我只需要使用技术人员的界面并进行例行维护和服务更改。

What keeps me from changing this IP address to, let’s say, 60.61.62.75 and mess with another consumer’s internet access?

是什么让我无法将此IP地址更改为60.61.62.75，并且使另一个用户的互联网访问陷入混乱？

Given the above, what keeps you from changing your IP to one that your ISP hasn’t specifically given to you is a server that is instructing your modem what it can and can’t do. Even if you somehow broke into the modem, if 60.61.62.75 is already allocated to another customer, then the server will simply tell your modem that it can’t have it.
鉴于上述情况，阻止您将IP更改为ISP未专门提供给您的IP的服务器是一台服务器，它指示调制解调器它可以做什么和不能做什么。即使您以某种方式闯入了调制解调器，如果60.61.62.75已经分配给另一位客户，服务器也会简单地告诉您的调制解调器它无法使用它。

David Schwartz offers some additional insight with a link to a white paper for the really curious:

David Schwartz提供了一些额外的见解，并提供了一个白皮书链接，以帮助您真正好奇：

Most modern ISPs (last 13 years or so) will not accept traffic from a customer connection with a source IP address they would not route to that customer were it the destination IP address. This is called “reverse path forwarding”. See BCP 38.
大多数现代ISP(最近13年左右)都不接受来自具有源IP地址的客户连接的流量，如果源IP地址是源IP地址，则它们将不会路由到该客户。这称为“反向路径转发”。参见BCP 38 。

Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

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