My GNUnet and Tor node

[As of early October 2016 my Tor configuration is stabilizing, but should still be considered tentative; I've not actually setup GNUnet yet. This message will disappear when I'm finished and everything is up in production.]

If you're reading this page it's not unlikely that you found the IP address on your logs, as a client accessing your machine. I intentionally made this page easy to find by also associating a DNS PTR record to the IP address: resolves to the name, which is supposed to lead you here.

Who I am

I am Luca Saiu. You can find information about me on my main page. I chose the domain name, but I'm not a hacker in the sense meant my journalists nowadays: I am a free software hacker, someone who loves to program and tinker with computer systems in a creative way. I have no interest whatsoever in attacking your computer or accessing your hidden data without authorization. Quite the opposite, I believe in respecting everyone's privacy and in the right of keeping personal communication secret. I vocally oppose surveillance and any form of censorship, including the censorship of ideas I disapprove of.

The purpose of this server

Along with other services used by me, some public such as email and web plus a few private ones, this server hosts GNUnet services and a Tor exit node, provided for the benefit of the global community. I don't gain anything from this personally — in fact the additional IP address comes at a cost for me, and I pay for bandwidth. Hosting a GNUnet and Tor node is just a way for me to give back to the community which makes anonymous uncensored communication possible, and also to help people living under oppressive regimes to exchange information with less fear of personal harm. The anonymity provided by networks such as Tor and GNUnet gets stronger as more hosts are involved in them, which makes adding every new host important.

I plan to keep my host active in the long term.

So, some attack attempt apparently originated from this host...

I'm sorry to hear it if that's the case.

It's quite possible that some user tried to abuse your services passing thru Tor or GNUnet, and at the time her traffic happened to come out of my exit node. Of course I have no control over this, and me filtering outbound traffic would defeat the whole purpose of anonymous, uncensored communication. For the same reason I keep no routing logs.

GNUnet and Tor are part of the network infrastructure, like TCP/IP and DNS. The infrastructure has not been conceived with malicious intents, but abuse is possible. Of course you should consider that the same identical attack might come tomorrow from a different, non-Tor node: the only possible conclusion is that, unfortunately, you'll have to make your own server secure. The presence of anonymizing services between the attacker and you shouldn't really affect your system administration work.

All the traffic originating from comes from GNUnet or Tor and its content is not controlled by me, except for the occasional HTTP exchange to serve this web page. All the other services on this machine actually managed by me use a different IP address.

My GNUnet configuration

[Still to come]

My Tor configuration

This machine runs a small Tor exit node called ageinghacker. Its fingerprint is 26AD3C1C18F1CD2B357A33FA7652A906DB13A8CC.

In production my node should have the flags Running, Valid and Stable. It currently doesn't serve directories, but this might change in the future. Realistically ageinghacker will not become a Guard node, as that would require quite a lot of bandwidth. Exits are scarcer than guards anyway.

It turns out that five out of eight authorities refuse to grant my node the Exit flag, presumably because of its limited bandwidth. If at some point in the future I upgrade my server to get more total bandwidth I will also reserve more bandwidth to Tor, but I don't plan to do that right now. In the mean time, despite not having the Exit flag, my node is still being used as an exit — I can usually see about ten exit connections active at any given time.

I aim at keeping my node online and working all the time every day, even at the cost of reducing its bandwidth. This is different from what the Tor documentation suggests, but I consider having more relays active to improve anonymity, and particularly having more exit nodes, to be a higher priority than high-performance support for video and games.

[hacker emblem]

Luca Saiu
Last modified: 2016-12-25

Copyright © 2016 Luca Saiu
Verbatim copying and redistribution of this entire page are permitted provided this notice is preserved.