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As far as I know, it is possible to have multiple A records for one host - GitHub Pages for apex domain is an example:

185.199.108.153

185.199.109.153

185.199.110.153

185.199.111.153

It is done for load balancing, Geo DNS purposes, etc.

So, what about several CNAME records for www? I have seen the setup for one domain recently that looked something like this:

www CNAME whispering-willow-5678.herokudns.com.

www CNAME autumn-sunset-1495.herokudns.com.

and it somehow managed to work via www.

My questions relate to the CNAME record particularly.

  1. Are these CNAME records queried in turn?

  2. Is it possible to have the configuration (with multiple CNAME) this way or is it a blunder?

  3. Can such configuration be used for load balancing purposes or something?

t7e
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1 Answers1

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From a DNS zone perspective it is valid syntax for most record types to have multiple identical resource records with the same name and type that only differ in their value.
That is not only valid syntax for A and AAAA records, but also commonly seen with NS and MX records. 

example.com. IN NS ns1.example.com.
example.com. IN NS ns2.example.com.

Your example appears to be intended as round robin DNS with all the inherent limitations in how effective that will be for load balancing. (It depends on both name server software, the resolver library and the client application how multiple records get ordered and how they will be used: if only the first, alternate, random or all records in (random) order are tried)

Bob
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