To set up a CNAME record on your 123-reg domain name, please do the following:
'CNAME' (canonical name) records are a pointer to another name already in DNS.
Firstly, you need to ensure your domain is pointed to our nameservers:
- ns.123-reg.co.uk
- ns2.123-reg.co.uk
If the domain is not pointed to the 123-reg nameservers, you will be unable to manage them from the 123-reg control panel.
For more information on changing your nameservers please view the following article:
How do I change the nameservers for my domain name?
Please Note: It will take between 24 - 48 hours for the new DNS records to become active.
2
In the Domain names section, select the relevant domain name in the drop-down list and click on the Manage button.
3
Scroll down to the Advanced Domain Settings section and click on the Manage DNS (A, MX, CNAME, TXT) link.

4
From the Advanced DNS tab.

5
Select CNAME from the Type drop down list in the Add new entry section.

6
In the Hostname field enter www
7
In the Destination CNAME field enter the record to where domain will point.

8
Click on the Add new entry button to save the new record.
9
If this record is to replace an existing record you can delete the original record by pressing the delete button.

Please Note: It will take between 24 - 48 hours for the new DNS records to become active.