CNAME records let you alias one domain name to another, but they come with important restrictions that trip up many people. This guide covers correct usage and common mistakes.
What a CNAME Record Does
Type: CNAME
Name: www
Value: yourdomain.comThis tells DNS resolvers "for www.yourdomain.com, look up yourdomain.com instead" — the actual IP resolution happens through whatever record exists at the target.
Rule 1 — CNAME Cannot Be Used at the Root/Apex Domain
You cannot create a CNAME for yourdomain.com itself (only for subdomains like www) in standard DNS — the root domain must use an A or AAAA record instead. Some DNS providers offer a proprietary workaround (often called "ALIAS" or "ANAME" records) that behaves like a CNAME but is allowed at the apex.
Rule 2 — A CNAME Cannot Coexist with Other Records on the Same Name
If app.yourdomain.com has a CNAME record, it cannot simultaneously have an MX, TXT, or A record — DNS specifications require a CNAME to be the only record for that exact name.
Common Use Cases
Pointing www to the Root Domain
Type: CNAME
Name: www
Value: yourdomain.comPointing a Subdomain to a Third-Party Service
Type: CNAME
Name: shop
Value: shops.myplatform.comCommon when using a hosted service (e-commerce platform, help desk tool) under your own subdomain.
Domain Verification for Third-Party Services
Many services ask you to add a specific CNAME record to prove domain ownership before activating a feature (custom domains, SSL certificates issued by that service).
CNAME vs A Record: Which to Use
| Scenario | Use |
|---|---|
| Root domain (yourdomain.com) | A/AAAA record (or ALIAS if supported) |
| www subdomain | CNAME to root, or A record with the same IP |
| Pointing to a service with a changing IP | CNAME (more resilient to IP changes at the target) |
| Pointing directly to your own static VPS IP | A record is simpler and slightly faster to resolve |
Verifying a CNAME Record
dig CNAME www.yourdomain.com +shortCommon Mistakes
- Attempting to create a CNAME at the root domain (not supported by standard DNS)
- Adding a CNAME to a name that already has an MX or TXT record, causing a conflict
- Creating a CNAME chain (CNAME pointing to another CNAME pointing to another...) — adds unnecessary resolution latency and complexity; point directly to the final target when possible
Common Errors
"CNAME and other data" error when saving — another record type already exists at that exact name; remove or consolidate before adding the CNAME.
Subdomain doesn't resolve despite the CNAME being set — verify the target of the CNAME itself actually resolves correctly; a broken chain anywhere fails the whole lookup.
Related Articles
- DNS Fundamentals: A, AAAA, CNAME, MX, TXT & NS Records Explained
- How to Point a Domain to Your VPS (A/AAAA Records)
- How to Troubleshoot DNS Propagation Issues
