Common DNS Record Types Explained: A, AAAA, CNAME, MX, TXT, and More
DNS records define where your website goes, where your email arrives, and how outside services verify your domain. During migrations, understanding the major record types helps prevent the classic mistake of moving web traffic while breaking something else at the same time.
The Records That Matter Most in Migrations
- A and AAAA: point the website to IPv4 or IPv6 addresses
- CNAME: aliases one hostname to another, commonly for
www - MX: controls inbound mail delivery
- TXT: often used for SPF, DKIM, DMARC, and verification records
The Difference Between Web and Mail Changes
Updating the website usually means changing an A record or related web-routing record. Updating email usually means changing MX and sometimes SPF or DKIM. Those are separate decisions. A site can move correctly while email fails if the migration plan only looks at the web records.
A Safer Review Order
Check records in groups rather than one by one: first web routing, then mail routing, then verification and security records. That gives you a clearer inventory and makes it less likely that one provider switch silently removes something important.
Where Nameserver Mistakes Happen
One of the most common errors is changing nameservers when only an A record needed to change. That can replace the whole DNS setup instead of just moving the website. Always confirm whether the task is an individual record update or a full DNS-provider move.
Conclusion
DNS record knowledge is practical, not theoretical. The better you understand which record controls which service, the safer your migrations become and the easier it is to verify the new environment before you make anything live.