Add a prefix
Before you start
Cloudflare recommends that you switch any Advanced TCP Protection rules currently in mitigation mode to monitoring mode before adding a new prefix to Advanced TCP Protection. Refer to for more information on execution modes.
Go to Account Home > Application Security > DDoS > Advanced TCP Protection.
Under General settings > Prefixes, select Edit.
Expand the Add existing prefix section and select Add next to the prefix you wish to add.
Alternatively, enter a prefix and (optionally) a description in Prefix and Description, respectively, and select Add.