Route 53配置-更好的ALIAS A或ALIAS CNAME RRS [英] Route 53 Configuration - Which is better ALIAS A or ALIAS CNAME RRS

问题描述

问题：

在使用Route服务使用CloudFront或ELB等AWS服务配置Route 53时，最好使用ALIAS A记录还是ALIAS CNAME记录？ / p>

背景：

对此问题开发了一个有趣的话题，涉及ALIAS记录的好处。

线程链接

我的意图是创建此问题，以便可以在一个地方收集有根据的答案和知识。

解决方案

没有更好的答案，只有一个正确的答案：Alias RR类型必须与目标RR相同。对于CloudFront，S3，ELB等，CNAME类型的别名并不明智，因为目标不是CNAME，而是A。

是A别名=是和CNAME别名=否之间的选择，那么A别名=是仍然是更好的解决方案。

另一个问题的断言是Alias记录与CNAME等效，但仅用于区域顶点在这两个方面都不正确。

别名A记录会导致与CNAME行为类似的最终行为，但它们是首选的，因为它们只需要一个解析器操作（而不是两个）即可将DNS解析时间减少一半左右，并且因为当别名目标是AWS服务时，它们可以将您的每次查询成本降低为0。

Question:

When configuring Route 53 with AWS services such as CloudFront or ELB, which is better to use: an ALIAS A record or an ALIAS CNAME record?

Background:

An interesting thread developed on this question regarding the benefits of ALIAS records.

Thread Link

My intention is to create this question so that informed answers and knowledge can be collected in one place.

解决方案

There is no "better," there's only one correct answer: the Alias RR type must be the same as the target RR. For CloudFront, S3, ELB, etc., an Alias of type CNAME is not sensible, since the target is not a CNAME, it's an A.

But if the question is a choice between A alias=yes and CNAME alias=no, then A alias=yes is still the better solution.

The assertion at the other question is that Alias records are equivalent to CNAMEs but intended for the zone apex only is incorrect on both counts.

Alias A records cause ultimate behavior similar to CNAME behavior but they are preferred because they cut the DNS resolution time approximately in half by requiring only one resolver action, instead of two, and because they reduce your per-query cost to 0 when the alias target is an AWS service.

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