FIELD GUIDE
A record vs CNAME: address or alias?
Two record types solve different naming problems. Choose based on what you are pointing to.
A and AAAA identify addresses
An A record maps a DNS owner to an IPv4 address. An AAAA record maps it to IPv6. Multiple answers can exist at the same owner; a resolver returning several addresses does not establish a universal primary endpoint.
Address records are useful when you control or have been given stable service addresses. If the service changes its addresses, someone must update the records or the provider’s routing configuration.
api.example.com. 300 IN A 192.0.2.10
api.example.com. 300 IN AAAA 2001:db8::10
Documentation addresses only.CNAME identifies another name
A CNAME says that the owner is an alias for another DNS name. Resolving an address can therefore require following that alias and then obtaining A or AAAA data for the target.
When the service provider manages a hostname that can move between addresses, an alias may avoid copying its current IP into your zone. Follow the provider’s instructions and confirm that a CNAME is appropriate at that owner.
www.example.com. 300 IN CNAME edge.example.net.
edge.example.net. 300 IN A 192.0.2.10
Documentation example only.Do not ignore coexistence rules
A normal CNAME generally cannot coexist with unrelated record data at the same owner. A zone apex needs its SOA and NS records, so a plain apex CNAME is usually unsuitable.
DNS providers sometimes expose ALIAS, ANAME or flattening features. These are provider-specific controls and may produce public A/AAAA answers rather than a literal CNAME. Do not assume the control-panel label describes the wire response.
DNS aliasing is not an HTTP redirect
A CNAME does not change the URL displayed by a browser or select a different webpage path. After address resolution, the browser still makes an HTTP request for the original hostname, including its TLS and host-header requirements.
An HTTP 301 or 302 is a response from a web server and can direct the client to another URL. If your goal is to move visitors between website addresses, configure the appropriate web redirect as well as DNS.
Trace a chain carefully
Check the CNAME at the exact owner, then inspect the target. A loop or a failed intermediate query prevents a complete traversal. A product hop limit is a safety boundary, not a reason to claim the target is invalid.
Compare resolver views only after matching type and owner. Cached aliases and cached address records can expire at different times, so write down the TTLs rather than relying on a fixed propagation slogan.
Which should you publish?
Use the record type requested by the service you are configuring. If a provider gives an address, verify its expected stability. If it gives a hostname, ask whether an alias or provider-specific apex feature is required.
Test in a non-production environment where possible and keep the previous configuration for rollback. This site reads published DNS data; it does not edit your zone or prove that your application is ready.