domain name system - A DNS record for both www and non-www websites

For each website I have, I noticed that having just this A DNS record:

*.example.com   3600    A   0   192.1.2.3

will make http://example.com unavailable and having just this A DNS record:

example.com 3600    A   0   192.1.2.3

will make http://www.example.com unavailable.

Question: is it mandatory to have two A DNS records to support www and non-www

*.example.com   3600    A   0   192.1.2.3
example.com     3600    A   0   192.1.2.3

or is there a way to define both in one A DNS record?

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PS: If it's mandatory to have two records, would you use:

www.example.com 3600    A   0   192.1.2.3
example.com     3600    A   0   192.1.2.3

or would you do it this way:

www.example.com 3600    CNAME example.com

example.com     3600    A   0   192.1.2.3

?

Answer

Short answer: Yes.

Longer: I would suggest you adding exactly www.example.com and not *.example.com unless you don't want to ever use any sub-domain like john.example.com and jane.example.com, etc....

Also, do not forget to configure your apache/nginx (which ever you use) to accept connections for both domain names.