You can buy an exclusive WAF IP address to protect a specific domain.

What is an exclusive IP address

By default, each WAF instance has one IP address that can be used to protect multiple domains. If you want to enable exclusive protection for a single domain, you can buy an exclusive IP address for your WAF instance.
Note An exclusive IP address can protect only one domain.

If a domain is compromised by DDoS attacks, an exclusive WAF IP address that protects this domain can help prevent other domains protected by the same WAF instance from access failure. By default, a WAF instance uses the same IP address to protect all the domains. If this IP address enters the black hole due to DDoS attacks on one of the domains, the other domains protected by the WAF instance also cannot be accessed. We recommend that you buy exclusive WAF IP addresses to protect important domains from access failures in the preceding situation.

Buy an exclusive WAF IP address

You can specify the number of exclusive IP addresses when you buy a subscription-based WAF instance.
Note If you have already bought a subscription-based WAF instance, you can upgrade the WAF instance to enable more exclusive IP addresses.

Assign and enable an exclusive IP address

Log on to the WAF console, and choose Management > Website Configuration. Find the domain that you want to assign an exclusive IP address to, and set the protection resource to Shared Cluster and Exclusive IP.
After you enable an exclusive IP address for a domain, the CNAME record of this domain is automatically resolved to the exclusive IP address. You can ping the CNAME record to check whether it has been automatically resolved to the exclusive IP address.
Note If the domain is resolved through the A record instead of the CNAME record, you must ping the CNAME record of the domain to obtain the exclusive WAF IP address, and manually resolve the domain to the exclusive WAF IP address.