Top Deliverability’s Blog
WttW: The trouble with CNAMEs
- September 7, 2023
- Posted by: Top Deliverability
- Category: Industry News Word to the Wise
Word to the Wise just released another insightful blog:
When you query DNS for something you ask your local DNS recursive resolver for all answers it has about a hostname of a certain type. If you’re going to a website your browser asks your resolver for all records for “google.com” of type “A”1 and it will either return all the A records for google.com it has cached, or it will do the complex process of looking up the results from the authoritative servers, cache them for as long as the TTL field for the reply says it should, then return them to you. There are dozens of different types of records, AAAA for IPv6 IP addresses, MX for mailservers, TXT for arbitrary text, mostly used for various sorts of authentication (including SPF, DKIM and DMARC). And then there’s CNAME. CNAME stands for “Canonical Name” and means “Go and ask this different question instead”. If you have a DNS record
Read more here: The trouble with CNAMEs
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