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Alibaba Cloud DNS:CNAME record parsing logic optimization

Last Updated:Jul 09, 2025

Background

To provide the best intelligent parsing experience for Cloud DNS users, we will optimize the CNAME record parsing logic before May 31, 2019. This optimization will prevent CNAME records from interfering with the priority matching of intelligent parsing lines.

Adjustment method

Scenario 1: www.dns-example.com Overseas: A record "1.1.X.X" Default: CNAME record "www.aliyun.com"

User Queries

Old response results

New response results

Domestic users query A record

CNAME record "www.aliyun.com"

CNAME record "www.aliyun.com"

Overseas users query A record

A record "1.1.X.X"

A record "1.1.X.X"

Domestic users query AAAA record

CNAME record "www.aliyun.com"

CNAME record "www.aliyun.com"

Overseas users query AAAA record

Responds with CNAME record "www.aliyun.com"

Does not respond with CNAME record "www.aliyun.com"

Scenario 2: www.dns-example.com Overseas: AAAA record "2400:3200:2000:10::1" Default: CNAME record "www.aliyun.com"

User Queries

Old response results

New response results

Domestic users query A record

CNAME record "www.aliyun.com"

CNAME record "www.aliyun.com"

Overseas users query A record

Responds with CNAME record "www.aliyun.com"

Does not respond with CNAME record "www.aliyun.com"

Domestic users query AAAA record

CNAME record "www.aliyun.com"

CNAME record "www.aliyun.com"

Overseas users query AAAA record

AAAA record "2400:3200:2000:10::1"

AAAA record "2400:3200:2000:10::1"

Compatible configuration

With these optimization adjustments, when a CNAME record exists in the default line and only an AAAA record is added to the overseas line, overseas users querying the domain will not be able to access the IPv4 address of the CNAME domain. If you want overseas users querying the domain to still access the IPv4 address of the CNAME domain under the default line, you can add an IPv4 address directly under the overseas line for compatibility. For example:

www.dns-example.com Overseas: AAAA record "2400:3200:2000:10::1", A record "1.1.X.X" Default: CNAME record "www.aliyun.com"