PeerBlock for Android allows rooted users to make sure applications aren’t talking to anyone you don’t want them to by downloading and implementing blocking rules. If you’ve ever used ad blocking apps or an RBL for torrenting, you’re familiar with the general concept of peer blocking. This exists to keep your device from talking to a list of devices it doesn’t trust, or to allow your apps to only talk to trusted sources.
PeerBlock for Android runs over the XPosed Framework, so you’ll need to have that installed first.
While peer blocking has long been a staple of people attempting to not be tracked by the MPAA or various anti-piracy groups while torrenting, there are a serious boatload of blocklists that are useful for the everyday law-abiding consumer. Blocklists exist so that you can skip any piracy related sites, porn, ads and trackers, proxies, advertisements, spyware, hijacked websites, or anything thought to contain pedophiles.
What blocklists you choose, and what options you set in PeerBlock for Android, can keep you, your family, or your child from accidentally wandering into something that might have lasting consequences. Or it might not, since the lists aren’t always perfect and blocking millions of hosts sometimes doesn’t catch enough.
You can even block entire continents if you have no business with them, as long as you have their IP ranges and a little time to make a blocklist-style text file. It’s still a work in progress and the author claims it will eat your cat, but it should be safe for root users without feline friends.[xda-developers]