Setting a DNS CNAME (Canonical Name) record for your domain names

Running a domain name is a multi-sided process thanks to the many DNS management possibilities offered by web hosting providers. Most of the hosts today offer multiple options for control over your domain's DNS settings, among them being the CNAME Records.

Content:

CNAME Records
DNAME record

CNAME Records

CNAME record is an abbreviation of Canonical Name Records, which is responsible for the aliases of the real host name of a computer, all enabled by DNS. It is needed when multiple domain names are resolved to one and the same IP address by a DNS server. It is important to know that a computer can have an unlimited number of CNAME aliases, but you must set a separate CNAME record in the database for each one of them.

Examples:

; zone fragment for example.com
$TTL 2d ; zone default = 2 days or 172800 seconds
$ORIGIN example.com.
....
server1 IN A 192.168.0.5
www IN CNAME server1
ftp IN CNAME server1
; zone file fragment for example.com
joe IN A 192.168.254.5
www IN CNAME joe ; canonical name is joe.example.com.
www IN CNAME joe.example.com.
; exactly the same as above
ftp IN CNAME www.example.com. ; not very good practice
; better practice to achieve same
; result as ftp CNAME above
; by re-defining the same physical host with 2 A records
ftp IN A 192.168.254.5
; next line redirects marta.example.com to
; maria.another.com
marta IN CNAME maria.another.com.

Using our advanced Custom DNS Manager tool, NTC Hosting customers are able to add, edit or delete CNAME records with a few mouse clicks. To add a CNAME record you need only to log in your web hosting control panel, to navigate to the Custom DNS Records section and to choose CNAME from the 'Type' drop-down list.

Then you need to add the URL you wish your domain to point to and adjust the TTL settings (they are set to 3600 seconds by default).

You may need to set CNAME records to your domain(s) on various occasions - if you need to point a subdomain to an external server (different from the one of your host) without having to use the IP address of that server directly; when you wish to create generic names or when you rename a host and do not need its current name anymore.

Through the Custom DNS Records section of your web hosting Control Panel with NTC Hosting you can set your own CNAME records to your domain name(s). Simply choose the domain name from the drop-down list and input the corresponding CNAME record value.

Note: A CNAME record must always point to an IP address or an hostname. If a CNAME entry is pointed to another CNAME records, this can cause an DNS loop. Other DNS records should also not be pointed to a CNAME record.

DNAME record

A DNAME record is very much alike the CNAME record, but while the CNAME record only applies for one name, with a DNAME record one can create alias for all the records for a domain or a sudbomain. However, using DNAME records causes a lot of works for the resolvers, which is why it's used should be limited, and just for a short time period.

Example of a DNAME record:

research.example.com	IN DNAME	r-and-d.example.com
military.r-and-d.example.comi	IN A	192.168.0.5
fuel.r-and-d.example.com	IN A	192.168.0.4

This way, all records for r-and-d.example.com will also be present for research.example.com and fuel.r-and-d.example.com will return the same result as fuel.research.example.com.