Unit 9 · Ship it and keep it alive
A record vs CNAME: which DNS record to use
An A record points a name at a numeric IP address, like 76.76.21.21. A CNAME points a name at another name, like cname.host-dns.com. Ask: is the value a number or a name?
The mix-up
What people often think
“Any record that points the site somewhere is an A record.”
What the tutor says
An A record points to a numeric IP address. When the value is another name, like cname.host-dns.com, it is a CNAME.
Is the value a number or a name?
How it works
Hosts often ask for a CNAME on www and an A record on the bare domain. Follow their instructions exactly.
A name can have only one CNAME. Adding a second record does not override the first; it creates a conflict. Edit the existing record instead of stacking a new one.
An example
cornerbakery.ca. A 76.76.21.21
www.cornerbakery.ca. CNAME cname.host-dns.com.Close cousins of this mix-up
The tutor watches for these in the same lesson.
“Adding another record will override the old one.”
A name can have only one CNAME. Edit the existing record instead of stacking a new one.
Practise it with a tutor watching
Domains and DNS
Point a domain at a host, read DNS records, and fix a broken one without panicking about the wait.
Free with an account. The first two units need no account.