What is a CNAME?
A CNAME record is a type of DNS record that maps an alias name to a true or canonical domain name. CNAME records are typically used to map a subdomain such as www or mail to the domain hosting that subdomain’s content. For example, a CNAME record can map the web address mybestdeals.com to the actual web site for the domain secondstreetapp.com. CNAME records must always be pointed to another domain name, never to an IP-address.
How it works
CNAME records are stored by your domain host and therefore must be changed with the host. One value identifies the alias you're creating the record for. The other value identifies the domain the alias should point to.
A CNAME record can direct the web address www.bestdeals.com to a web site with the domain secondstreetapp.com. CNAME records make it easy to run multiple services from one IP address. Each CNAME record associates a service with a domain name, not a physical IP address.
CNAME Setup Instructions
For specific host setup instructions click here.
1. Sign in to your domain's account at your domain host.
2. Locate the page for updating your domain's DNS records. The page might be called something like DNS Management, Name Server Management, or Advanced Settings.
3. Locate the CNAME records for your domain. You may already have one or more records resembling this.
4. Add a CNAME record with the correct values for your desired use case. Or modify an existing CNAME record if the one you want to change is already there. To find out exactly what values to enter, see CNAME record values.
5. Save your changes and wait until they take effect.
Query for CNAME records only, precede you domain name with "cname:" as in
Verify the results. Depending on their purpose, the values returned should match those on the CNAME record values page.
CNAME Vs. A Record
A CNAME and A Record are standard DNS records, whilst ALIAS and URL records are custom DNS records provided by DNSimple. Both of them are translated internally into A record to ensure compatibility with the DNS protocol.
Differences Between CNAME and A Record
1. The A record maps a name to one or more IP addresses, when the IP are known and stable.
2. The CNAME record maps a name to another name. It should only be used when there are no other records on that name.
3. The ALIAS record maps a name to another name, but in turns it can coexist with other records on that name.
4. The URL record redirects the name to the target name using the HTTP 301 status code.
The A, CNAME, ALIAS records causes a name to resolve to an IP. Vice-versa, the URL record redirects the name to a destination. The URL record is simple and effective way to apply a redirect for a name to another name, for example to redirect mybestdeals.com to secondstreetapp.com.
The A Record name must resolve to an IP, the CNAME and ALIAS record must point to a name.
Which One to Use
1. Use an A record if you manage what IP addresses are assigned to a particular machine or if the IP are fixed (this is the most common case)
2. Use a CNAME record if you want to alias a name to another name, and you don’t need (such as other records (such as MX records for emails) for the same name
3. Use an ALIAS record if you are trying to alias the root domain (apex zone) or if you need other records for the same name
4. Use the URL record if you want the name to redirect (change address) instead of resolving to a destination.