Raspberry Pi Tor Relay

Tor (short for The Onion Router) is a system intended to enable online anonymity. The Tor client software directs internet traffic through a worldwide volunteer network of servers to conceal a user's location or usage from anyone conducting network surveillance or traffic analysis. Using Tor makes it more difficult to trace Internet activity, including "visits to Web sites, online posts, instant messages and other communication forms", back to the user and is intended to protect users' personal freedom, privacy, and ability to conduct confidential business by keeping their internet activities from being monitored.

So obviously, TOR needs a large amount of servers and as TOR network is not a commercial organisation, it requires voluntary supporters. You can be one of them and turn your Raspberry in a TOR relay.

You need the following parts:

- Raspberry Pi
- power supply
- network cable/connection to the Internet
- SDcard with Raspbian (you can find all necessary installation intructions here: http://www.raspbian.org/RaspbianInstaller)

For security reasons you should not work as "root" all the time, you can fix this problem with the following steps:

Open a terminal

    apt-get install sudo
adduser tor
    passwd tor

this creates the user "tor" and let's you set a password. Please use at least 8 digits (numeric, alphanumeric and special characters)

Now we have to to add the tor user account to the list of sudoers:

    nano /etc/sudoers

Add the line

    tor ALL=(ALL) ALL

Now we'll install the latest security patchess and updates. Please do this  regularly!!!

    sudo apt-get update
    sudo apt-get upgrade

Now that the base setup is done, we have to configure network interface, open a terminal and use this command:

ifconfig

This shows you your actual configuration:

eth0      Link encap:Ethernet  HWaddr 00:23:54:40:66:df 
          inet addr:192.168.0.20  Bcast:192.168.0.255  Mask:255.255.255.0

write down inet addr and mask

then type:

sudo nano /etc/network/interfaces

You will find a line like this:

              iface eth0 inet dhcp

So as we see the Raspberry obtains an IP adress from the local DHCP server. If you want a static IP you hould change this to:

iface eth0 inet static
address 192.168.0.20 <- chose an IP that fits to your network! This is only an example!
netmask 255.255.255.0 <- change to the settings that fit to your network
gateway 192.168.0.1  <- type in the correct IP adress of your gateway.

Now we need to edit the TOR configuration file . You can find it here: /etc/tor/torrc. Open this file with your favourite text editor an add/change these settings:

SocksPort 0
Log notice file /var/log/tor/notices.log
RunAsDaemon 1
ORPort 9001
DirPort 9030
ExitPolicy reject *:*
Nickname xxx (you can chose whatever you like)
RelayBandwidthRate 100 KB  # Throttle traffic to 100KB/s (800Kbps)
RelayBandwidthBurst 200 KB # But allow bursts up to 200KB/s (1600Kbps)

If your Raspberry sits behind a firewall, you'll have to configure its settings. To allow other nodes in the TOR network to contact your TOR relay, you have to open the ports 9030 and 9001. 9030 is needed for the directory service and 9001 for relay operation. Please refer to your firewll manual, there are to many to explain how to do it for every single firewall.

sudo /etc/init.d/tor restart

TOR is now restarted. Now we have a look at the log file (less /var/log/tor/log). If everything is fine, you'll find an entry like

Oct 18 22:59:21.104 [notice] Tor has successfully opened a circuit. Looks like client functionality is working.

To use Tor, you need a Tor client, which routes all your Internet traffic through the Tor network. To make you "invisible", the traffic travels through several randomly selected relays (run by volunteers like you and your Raspberry), before exiting the Tor network and arriving at your destination. This prevents your Internet service provider and people monitoring your local network from viewing the websites you access. It also prevents the websites themselves from knowing your physical location or IP address – they’ll see the IP address and location of the exit node instead. Even the relays don’t know who requested the traffic they’re passing along. All traffic within the Tor network is encrypted.

The first picture shows you how it works

An example: Let’s say you access instructables.com through Tor. Your Internet service provider and local network operator can’t see that you’re accessing this site – they just see encrypted Tor traffic. The Tor relays pass your traffic along until it eventually reaches an exit node. The exit node talks to instructables.com for you – from the perspective of this site, the exit node is accessing their website. (Of course, traffic can be monitored at the exit node if you’re accessing an unencrypted website.) The exit node passes the traffic back along the relays, and the relays don’t know where it ends up.

This makes it possible for Tor to offer anonymity and a path through Internet censorship and monitoring – people living under repressive regimes with censored Internet connections can use Tor to access the wider Internet without fear of reprisal. Whistleblowers can use Tor to leak information without their traffic being monitored and logged.

All this nice features have their price. Browsing with Tor makes it really slower. So you might now be able to see youtube videos, that are blocked in your country, but it may take some time until the video loads.

So how can you get this client and install it?

This depends on your operating system and browser. There are many good tutorials out there for almost every possible combination. You can find many other good (video) tutorials out there, but i think the following links should give you enough information for your first steps:

Windows: https://www.torproject.org/docs/tor-doc-windows.html.en

Linux/Unix/BSD: https://www.torproject.org/docs/tor-doc-unix.html.en

Debian/Ubuntu: https://www.torproject.org/docs/debian.html.en

Mac OSX: https://www.torproject.org/docs/tor-doc-osx.html.en

and last but not least:

Android: https://www.torproject.org/docs/android.html.en

Last words:

Remember not to provide any personal information – say, by logging into an account associated with you – while using the Tor browser, or you’ll lose the anonymity.