If they have a DNS records page, you’d have to make sure all those records exist here as well.
Generally, when you add a site to Cloudflare, Cloudflare will guess at thousands of possible hostnames to see if your current DNS has them, then add them here automatically.
IP address resolution (at least one required for each domain)
A and AAAA
Purpose : A and AAAA Records direct browser requests to an origin web server (A for IPv4 addresses and AAAA for IPv6 addresses).
Fields :
Name: A subdomain or the root domain, which must:
Be 63 characters or less
Start with a letter and end with a letter or digit
Only contain letters, digits, or hyphens (underscores are allowed but discouraged in A and CNAME records)
IPv4/IPv6 address : Your origin web server address (cannot be a Cloudflare IP)
TTL : Time to live (only available if traffic is not proxied through Cloudflare)
Proxy status : Select the cloud icon to change proxy status. If your record is proxied, that means that Cloudflare is:
Hiding the origin IP address from attackers
Caching
Storing an HTTPS certificate on its edge servers
Providing support for Page Rules, Caching, Firewall, and more
Notes :
If you want to sustainably spread traffic across multiple domains, check out Cloudflare Load Balancing.
Though you could spread traffic with multiple A or AAAA records — because Cloudflare alternates requests based on each record — this approach might send your traffic to unreachable IP addresses. Load balancing provides a much more reliable solution.
CNAME
Purpose :
CNAME records direct browser requests to an origin web server, but — unlike an A or AAA record — do so via a hostname like www.example.com instead of an IP address .
Fields :
Name: A subdomain or the root domain, which must:
Be 63 characters or less
Start with a letter and end with a letter or digit
Only contain letters, digits, or hyphens (underscores allowed but discouraged)
Target : The hostname where traffic should be directed
TTL : Time to live (only available if traffic is not proxied through Cloudflare)
Proxy status : Select the cloud icon to change proxy status. If your record is proxied, that means that Cloudflare is:
Hiding the origin IP address from attackers
Caching
Storing an HTTPS certificate on its edge servers
Providing support for Page Rules, Caching, Firewall, and more
Notes :
You can use CNAME records to point to other CNAME records ( www.example2.com → www.example1.com → www.example.com ), but the final record must point to a hostname with a valid IP address (and therefore a valid A or AAAA record).