Every day dozens of millions of people share files using BitTorrent, willingly exposing their IP-addresses to the rest of the world.
For those who value their privacy this is a problem, so many sign up with a VPN provider or torrent proxy service. This is fine, but some people then forget to check whether their setup is actually working, which is not always the case.
Some torrent clients may be vulnerable to leaks, or people simply forget to configure their client properly, which may involve ticking a few extra checkboxes and disabling features such as DHT and PEX.
So how do you check if your VPN and proxy are working properly? While it’s easy enough to test your web IP-address through one of the many IP-checking services, checking the IP-address that’s broadcasted via your torrent client is more complex.
There are a few services that offer a “torrent IP check” tool but these are generally limited to responses from HTTP trackers. Luckily, a new project allows people to dive a bit deeper.
Doileak is free a service that runs IP-address checks to test for general leaks, but also more specific torrent checks.
After loading a test torrent it will report back the IP-address your torrent client is using to connect to other peers. In addition to an HTTP tracker, it also has an UDP version, which is crucial as UDP trackers are more likely to leak information.
Furthermore, Doileak also reports the various DNS requests your torrent client is using, which may also be a weak link for some.
Doileak torrent results
Everything is functioning properly as long as your residential IP-address or your Internet provider’s DNS server doesn’t show up in the torrent sections. For VPN users the web and torrent IP-address should be the same, but for proxy users the two IPs are different.
Talking to TorrentFreak, Doileak founder Tobias warns that not all VPN services are as effective as they should be, so encourages people to check their setup.
“BitTorrent support initially wasn’t on my todo list, but after some research it became clear that a lot of torrent users believe they are anonymous, while they are broadcasting their real IP-address,” he says.
In a separate article Tobias identifies several weak spots for torrent users, including UDP leaks and the DHT vulnerability.
Users who are interested in their setup can run the test over at Doileak.