According to core DNS protocols (RFC 1912), you cannot add a CNAME record to your root domain (apex) because a CNAME cannot coexist with other essential records like MX (email) or NS (nameservers). Attempting to do so will break your domain's email routing. To solve this, use an A Record pointing to a static IP, or configure a www redirect.
Root Domain vs Subdomain
Root domain (apex): The bare domain without any prefix, just example.com. In DNS managers, this is often represented as @.
Subdomain: Anything with a prefix, www.example.com, blog.example.com, api.example.com. These can freely use CNAME records.
When PaaS providers like Heroku, Netlify, or Vercel give you a hostname to point to (e.g., your-app.herokuapp.com), they expect a CNAME. That works for www, but not for the root.
The Technical Conflict: CNAMEs Override Everything
A CNAME record is "canonical", it declares that one hostname is an alias for another. DNS specification requires that if a CNAME exists, no other record types can exist for that hostname.
Your root domain requires NS records (nameservers), MX records (email), and SOA record (zone authority). A CNAME at root invalidates all of these, NS breaks, domain stops resolving; MX breaks, email stops arriving.
This isn't a registrar limitation, it's fundamental DNS architecture defined in RFC 1912.
Decision Framework: A Record vs ALIAS vs Redirect
A Record: Works at root, but requires a static IP address. If your host only provides a hostname (no IP), this won't work.
ALIAS/ANAME: A proprietary record type that acts like a CNAME but resolves at the DNS level. Not universally supported, NameSilo does not currently offer ALIAS/ANAME records.
www redirect: Set CNAME on www, then redirect root to www. This is the most reliable workaround.
Implementation Steps: The Standard Workaround
Step 1: Point www to Your Host Create a CNAME record for www pointing to your provider's hostname (e.g., your-app.herokuapp.com).
Step 2: Apply Secure WWW Redirect Template In NameSilo's DNS Manager, apply the "Secure WWW Redirect" template. This forwards example.com to www.example.com via 301 redirect.
Step 3: Verify MX Records Ensure your MX records remain intact for email routing. The redirect doesn't affect email.
Step 4: Test Both URLs Visit both example.com and www.example.com. The root should redirect seamlessly to www.
Common Mistakes
Forcing CNAME at root: Some DNS providers allow this and silently break your email. Don't do it.
Expecting ALIAS support everywhere: ALIAS records are provider-specific. Verify support before planning around this feature.
Forgetting the redirect: If you only set up www, root domain visitors see nothing. Always configure forwarding.
Using HTTP instead of 301: Use permanent (301) redirects for SEO benefits.
What This Means for You
NameSilo's DNS Manager supports the industry-standard workaround: CNAME on www plus root forwarding. While ALIAS/ANAME flattening isn't available, the redirect approach works reliably with any PaaS provider.
Frequently Asked Questions
Why is CNAME not allowed at the root?
CNAME records override all other records, breaking required NS and MX records.
A proprietary record that resolves like CNAME but works at root level.
Can I point my root domain to Heroku?
Yes, via A record or www redirect with CNAME.
Will a root CNAME break my email?
Yes. MX records cannot coexist with CNAMEs.
Another term for root/apex, domain without www prefix.
How do I redirect my root domain to www?
Use NameSilo's Secure WWW Redirect template in DNS Manager.
What is the difference between A Record and CNAME?
A Records point to IPs. CNAMEs point to hostnames.
Does NameSilo support ALIAS records?
No. Use www redirect instead.
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