Why wouldn't it be? You're not actually hosting a tracker in this case, only looking at incoming connections. And even if you do run a tracker, hard to make the case that the tracker itself is illega. Hosting something like opentrackr is like hosting a search engine, how they respond to legal takedown requests is where the crux is at, and whatever infra sits around the tracker, so police and courts can see/assume the intent. But trackers are pretty stupid coordination server software, would be crazy if they became illegal.
Why wouldn't it be? You're not actually hosting a tracker in this case, only looking at incoming connections. And even if you do run a tracker, hard to make the case that the tracker itself is illega. Hosting something like opentrackr is like hosting a search engine, how they respond to legal takedown requests is where the crux is at, and whatever infra sits around the tracker, so police and courts can see/assume the intent. But trackers are pretty stupid coordination server software, would be crazy if they became illegal.