There’s basically only one, listed towards the bottom of the guide in the repo: http://tracker2.postman.i2p/. And it’s “public” but only accessible via I2P. I tried to explain everything in the repo so let me know if I missed anything!

It’s not just the router. The officially recommended I2P torrent client, called I2PSnark, is also in Java and its a pain to get working in Docker. It’s not a bad torrent client, just feels like the official I2P tools still don’t have great support for modern Linux devops. Now that qBittorrent supports I2P the whole stack feels much more at home.

It’s true, you never really know what will be going through your router. I guess I just got over it after a few years of struggling with VPNs and port-forwarding. Just felt like the noose was getting tighter, especially after Mullvad stopped providing the feature. My stance is that if I ever knew that such content was going through my PC I would block it, but if it’s all encrypted then what can I do? Same reason why I support encrypted messaging apps - they can be used for harm but is that the fault of the tool? Though I recognize it’s a complex issue.

You might be interested in my tool wg-lockdown. I mainly use it on desktops but it should work on servers as well, it’s just an nftables config after all. It also shouldn’t interfere with UFW though you might want to double-check with some of the networking experts here.