How to test CloudFlare without changing your domain's name server
Yes, you should be able to test before you change your name servers. Here's what to do:
- Signup at www.cloudflare.com/sign-up and complete the signup through Step 4 when you're asked to update your name servers.
- Note the two name servers you are provided which will be in the format [name].ns.cloudflare.com.
- From a terminal, do a lookup to get the IP addresses your domain has been assigned. In Linux/Unix it'd be: dig @[name].ns.cloudflare.com yourdomain.com
- Repeat step 3 with all the subdomains you want to check.
- Update your localhost record to resolve the domain(s) to the IPs you found with the lookup.
- Browse the site from the same machine where you did the localhost update and traffic should pass through CloudFlare.
While this will work for a while, after 24 hours CloudFlare's system may detect that your name servers haven't updated and, in some cases, may return an error. However, this technique should allow you basic testing before you update your name servers.
To save future users from some headache, the above answer doesn't work anymore: https://community.cloudflare.com/t/ip-on-cloudflare-nameserver-is-not-masked-despite-orange-cloud/76137
From my understanding, you now need to change your nameserver.