Is Root domain CNAME to other domain allowed by DNS RFC?

dns cname
Geo picture Geo · Mar 17, 2009 · Viewed 15.6k times · Source

We are hosting the page of many of our customers. We want to be able to provide our customers with a subdomain of our own domain like customerpages.ourdomain.com so they can create a CNAME to this subdomain.

www.customer1.com CNAME customerpages.ourdomain.com.  {This will work just fine.}

But the situation is I don't know if all our customers will be able to place the following CNAME

customer1.com CNAME customerpages.ourdomain.com

This last CNAME looks like it's against the RFC of DNS.

Any thoughts will be appreciated.

Answer

Alnitak picture Alnitak · Mar 17, 2009

No, you can't do that - CNAME records can only exist as single records and not combined with any other resource record (DNSSEC records excepted).

There are explicit SOA and NS records always present at the top of each domain, so that prevents the use of the CNAME at the same part of the hierarchy.

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