We launched a new utility this week: Open Proxy Insights

Value:

Trusted service one can leverage to know if a site visitor is using an open proxy. Data is backed by actual testing, not 3rd party look-ups.

Usage (in a nutshell):

Include a JavaScript tag in your web page/site

Access a local variable (/subscribe to an event)

Know if a user is from an IP address presently or previously testing positive for being an open proxy.

Provide appropriate alternate workflows or messaging to user. 

Limitations/focus:

We currently have an obsessive focus on open proxies. Thus, with some confidence, if it is an open proxy in circulation, we'll properly flag it (as of this post, we are testing 594K proxies a day).

Road-map (things we could do in the future):

Expand the widget to do more expansive IP Address intelligence beyond simply using TheProxIsRight's vast aggregation and testing platform. It is formidable as-is, but focused. It has value, but probably has more value to a network attribution detection service to use as a trusted feed, than as the only thing a site owner uses to detect potential fraud.

Examine headers for proxy evidence, as we do in our anonymity tests for TheProxIsRight, or do a live evaluation from the browser via AJAX.

We could provide a preliminary finding (as we do now) and then do a live test using common ports to provide an updated score. (Note: We currently use a pub/sub architecture in JavaScript, so a site could just subscribe initially, and then hang around for updates.)

Aggregate (and test?) TOR exit nodes

Aggregate VPN exit nodes from common 3rd parties

Conclusion:

We put something out there. Please try it out. Please let us know if you have suggestions for improvement. Please let us know if there is a fantastic dirty IP Address widget out there we should take notice of.