PeerBlock is not available for Mac but there is one alternative that runs on macOS with similar functionality. The best Mac alternative is PeerGuardian, which is both free and Open Source. If that doesn't work for you, our users have ranked five alternatives to PeerBlock, but unfortunately only one of them is available for Mac. If you can't find an alternative you can try to remove all filters.
PeerGuardian is a privacy oriented firewall application. It blocks connections to and from hosts specified in huge blocklists (thousands or millions of IP ranges). Its origin seeds in targeting aggressive IPs while you use P2P.
Canada
Discontinued but still available, and still an alternative.