To enable correct IP matching when running an Invision Power Board 3 installation through Cloudflare, follow these directions:
1. Log into your IPB installation's ACP.
2. Go to System.
3. Under Overview go to Security.
4. Under Security Center click Security Settings.
5. Check "Trust IP addresses provided by proxies?" so it is green.
IPB4 description of "Trust IP addresses provided by proxies?"
If your network environment means requests are handled through a proxy (such as in an intranet situation in an office or university, or on a load-balanced server cluster), you may need to enable this setting so that the correct IP address is used. However, when enabled, a malicious user can abuse the system to provide a fake IP address. In most environments, this setting should be left off."