The firm will block IP addresses based on region, and Asia, Africa, Russia, and the Middle East are currently included on the company's block list. "While we appreciate that there are players in these regions who would enjoy playing on En Masse servers, it's unfortunate that the vast majority of internet traffic we see from these regions is from cyber-criminals relating to account theft, gold-farming and other hacking behavior," the company says.
En Masse will not initially block proxies, but "a proxy or server host will be blocked if it becomes a popular tool for criminal behavior," according to the release.
[Thanks to Stilllove for the tip!]
[Update: En Masse has responded with an official explanation of the changes. We've included the full statement behind the break.]
We had to change our stance on IP restrictions due to licensing and security issues. While we can't go into the reasons in detail, we would like to say that although these restrictions are not a panacea for preventing hacking, they are highly effective, and produce more positive results than might be expected. Like many game companies, our studio has been under continuous, sustained assault as hackers anticipate the launch of TERA. Our goal is to provide the best experience for TERA players in North America, which necessitates the change. We hope players disappointed by the change understand our reasoning, and we hope to extend the regions in which TERA is accessible in the future.