Once changed, the DNS A records for the site domain needs changing to the correct IP address. For sites which do not have their own SSL, this is the 89.21.20.136 IP address. For sites with their own SSL certificate a different IP address is required for each site.
This should normally be applied to both the “www” and “@” records so that both www.sitedomain.co.uk and sitedomain.co.uk point at our servers.
No email DNS records should be changed.
The additional c.sitedomain.co.uk, p.sitedomain.co.uk and s.sitedomain.co.uk subdomains used to server the site images and css files should be configured as DNS CNAME records pointing to the www.sitedomain.co.uk record.
Chris