CDN DNS 是如何工作的 [英] How does CDN DNS Work

问题描述

最近，我看到我在 CDN 上的介绍

Recently, I saw I introduction on CDN at

http://www.aflexi.net/technology/how-aflexi-cdn-作品

我想知道，为什么用户的网络浏览器会知道它需要联系洛杉矶的 Aflexi DNS 服务器，而不是由 ISP(如 AOL)提供的 DNS 服务器?

I was wondering, why user's web browser will know it need to contact Aflexi DNS Server in Los Angeles, but not DNS Server provided by ISP (Like AOL)?

谢谢！

推荐答案

您的 Internet 服务提供商可能会通过 DHCP 协议推送 DNS 服务器信息(当然，您可以在您的机器上本地覆盖此信息).这就是您的机器将如何配置 DNS 服务器以启动查询.

Your Internet Service Provider will likely push the DNS server information through the DHCP protocol (of course, you can override this information locally on your machine). This is how your machine will get configured with DNS servers to launch queries against.

CDN 的工作方式如下:依赖基于 CDN 交付其内容的公司将通过 CDN 提供商管理其域.当请求说域D时，机器将联系其配置的DNS服务器，并将被定向到相关域D的权威实体".从这一点开始，CDN DNS 服务器可以回复一个答案，该答案提供与最接近"请求来源的 IP 地址的绑定.

The way a CDN works is as follows: companies relying on CDN based delivery of their contents will manage their domains through a CDN provider. When a request comes for say domain D, a machine will contact its configured DNS server and will be directed to the "authoritative entity" for the domain D in question. From this point, the CDN DNS server can reply with an answer that provides a binding to an IP address "closest" to where the request originated.

属性最接近"是根据请求机器的 IP 地址确定的.尽管如此，根据此信息分配指标"并非易事:IP 地址"和物理位置"之间没有直接关联，这些重要信息对于向请求机器提供尽可能好的内容.

The property "closest" is determined, amongst other things, based on the requesting machine's IP address. It is nonetheless non-trivial to assign a "metric" based on this information: there is no direct correlation between "IP address" and "physical location", vital information for effecting as best as possible contents to the requesting machines.

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