In general resolvers look up one type and cache the result for that one type. CNAMEs are special; firstly clients never lookup CNAMEs, it's never the qtype. A C

In general resolvers look up one type and cache the result for that one type. CNAMEs are special; firstly clients never lookup CNAMEs, it's never the qtype. A CNAME is a special kind of answer that says "This name should be considered equivalent to this other name, go find out what that other name has" and as-such the CNAME is cacheable for queries of all types. It is a race condition, but this race condition only exists if you ignore the DNS RFCs and try to get behavior that DNS just plain doesn't support. I don't mean to point fingers, but in this case that's what happened; CloudFlare's behavior ignores the RFCs [1] and leads to nondeterministic results. [1] http://blog.cloudflare.com/zone-apex-naked-domain-root-domain-cname-supp http://blog.cloudflare.com/zone-apex-naked-domain-root-domai...