The A
and CNAME
records are the two common ways to map a hostname (“name”) to one or more IP addresses. There are important differences between these two records.
The A
record points a name to a specific IP. If you want blog.dnsimple.com
to point to the server 185.31.17.133
you’ll configure:
blog.dnsimple.com. A 185.31.17.133
The CNAME
record points a name to another name instead of to an IP. The CNAME source represents an alias for the target name and inherits its entire resolution chain.
Let’s use an example:
blog.dnsimple.com. CNAME aetrion.github.io.
aetrion.github.io. CNAME github.map.fastly.net.
github.map.fastly.net. A 185.31.17.133
We use GitHub Pages, and we set blog.dnsimple.com
as a CNAME
of aetrion.github.io
, which is a CNAME
of github.map.fastly.net
, which is an A
record pointing to 185.31.17.133
. This means blog.dnsimple.com
resolves to 185.31.17.133
.
An A
record points a name to an IP
. A CNAME
record can point a name to another CNAME
or to an A
record.