Tor FAQ
- General questions
- Compilation and Installation
- Running Tor
- Running a Tor client
- Running a Tor relay
- Running a Tor hidden service
- What happens to my donation?
What is Tor?
The name "Tor" can refer to several different components.
The Tor software is a program you can run on your computer that helps keep you safe on the Internet. Tor protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, and it prevents the sites you visit from learning your physical location. This set of volunteer relays is called the Tor network. You can read more about how Tor works on the overview page.
The Tor Project is a non-profit (charity) organization that maintains and develops the Tor software. The Tor Project is ...
What programs can I use with Tor?
There are two pieces to "Torifying" a program: connection-level anonymity and application-level anonymity. Connection-level anonymity focuses on making sure the application's Internet connections get sent through Tor. This step is normally done by configuring the program to use your Tor client as a "socks" proxy, but there are other ways to do it too. For application-level anonymity, you need to make sure that the information the application sends out doesn't hurt your privacy. (Even if the connections are being routed through Tor, you still don't want to include sensitive information like your name.) This second step needs to be done on a program-by-program basis, which is why we don't yet recommend very many programs for safe use with Tor.
Most of our work so far has focused on the Firefox web browser. The bundles on the download page automatically install the Torbutton Firefox extension if you have Firefox installed. As of version 1.2.0, Torbutton now takes care of a lot of the connection-level and application-level worries.
There are plenty of other programs you can use with Tor, but we haven't researched the application-level anonymity issues on them well enough to be able to recommend a safe configuration. Our wiki has a list of instructions for Torifying specific applications. There's also a list of applications that help you direct your traffic through Tor. Please add to these lists and help us keep them accurate!
Why is it called Tor?
Because Tor is the onion routing network. When we were starting the new next-generation design and implementation of onion routing in 2001-2002, we would tell people we were working on onion routing, and they would say "Neat. Which one?" Even if onion routing has become a standard household term, Tor was born out of the actual onion routing project run by the Naval Research Lab.
(It's also got a fine translation from German and Turkish.)
Note: even though it originally came from an acronym, Tor is not spelled "TOR". Only the first letter is capitalized.
Is there a backdoor in Tor?
There is absolutely no backdoor in Tor. Nobody has asked us to put one in, and we know some smart lawyers who say that it's unlikely that anybody will try to make us add one in our jurisdiction (U.S.). If they do ask us, we will fight them, and (the lawyers say) probably win.
We think that putting a backdoor in Tor would be tremendously irresponsible to our users, and a bad precedent for security software in general. If we ever put a deliberate backdoor in our security software, it would ruin our professional reputations. Nobody would trust our software ever again — for excellent reason!
But that said, there are still plenty of subtle attacks people might try. Somebody might impersonate us, or break into our computers, or something like that. Tor is open source, and you should always check the source (or at least the diffs since the last release) for suspicious things. If we (or the distributors) don't give you source, that's a sure sign something funny might be going on. You should also check the GPG signatures on the releases, to make sure nobody messed with the distribution sites.
Also, there might be accidental bugs in Tor that could affect your anonymity. We periodically find and fix anonymity-related bugs, so make sure you keep your Tor versions up-to-date.
Can I distribute Tor on my magazine's CD?
Yes.
The Tor software is free software. This means we give you the rights to redistribute the Tor software, either modified or unmodified, either for a fee or gratis. You don't have to ask us for specific permission.
However, if you want to redistribute the Tor software you must follow our LICENSE. Essentially this means that you need to include our LICENSE file along with whatever part of the Tor software you're distributing.
Most people who ask us this question don't want to distribute just the Tor software, though. They want to distribute the Tor bundles, which typically include Privoxy and Vidalia. You will need to follow the licenses for those programs as well. Both of them are distributed under the GNU General Public License. The simplest way to obey their licenses is to include the source code for these programs everywhere you include the bundles themselves. Look for "source" packages on the Vidalia download page and the Privoxy download page.
Also, you should make sure not to confuse your readers about what Tor is, who makes it, and what properties it provides (and doesn't provide). See our trademark FAQ for details.
Lastly, you should realize that we release new versions of the Tor software frequently, and sometimes we make backward incompatible changes. So if you distribute a particular version of the Tor software, it may not be supported — or even work — six months later. This is a fact of life for all security software under heavy development.
How can I get an answer to my Tor support mail?
Many people send the Tor developers mail privately, or send mail to our internal aliases like tor-webmaster, with questions about their specific setup — they can't get their firewall working right, they can't configure Privoxy correctly, or so on. Sometimes our volunteers can answer these mails, but typically they need to spend most of their time on development tasks that will benefit more people. This is especially true if your question is already covered in the documentation or on this FAQ. We don't hate you; we're just busy.
So if we don't answer your mail, first check the documentation page, along with this FAQ, to make sure your question isn't already answered. Then read "How to ask questions the smart way". If this doesn't help you, note that we have an IRC channel where you can ask your questions (but if they are still open-ended, ill-formed, or not about Tor, you likely won't get much help there either). Lastly, people on the or-talk mailing list may be able to provide some hints for you, if others have experienced your problems too. Be sure to look over the archives first.
Another strategy is to run a Tor relay for a while, and/or donate money or time to the effort. We're more likely to pay attention to people who have demonstrated interest and commitment to giving back to the Tor community.
If you find your answer, please stick around on the IRC channel or the mailing list and answer questions from others.
Why is Tor so slow?
There are many reasons why the Tor network is currently slow.
Before we answer, though, you should realize that Tor is never going to be blazing fast. Your traffic is bouncing through volunteers' computers in various parts of the world, and some bottlenecks and network latency will always be present. You shouldn't expect to see university-style bandwidth through Tor.
But that doesn't mean that it can't be improved. The current Tor network is quite small compared to the number of people trying to use it, and many of these users don't understand or care that Tor can't currently handle file-sharing traffic load.
What can you do to help?
- Configure your Tor to relay traffic for others. Help make the Tor network large enough that we can handle all the users who want privacy and security on the Internet.
- Help us make Tor more usable. We especially need people to help make it easier to configure your Tor as a relay. Also, we need help with clear simple documentation to walk people through setting it up.
- There are some bottlenecks in the current Tor network. Help us design experiments to track down and demonstrate where the problems are, and then we can focus better on fixing them.
- There are some steps that individuals can take to improve their Tor performance. You can configure your Firefox to handle Tor better, you can use Polipo with Tor, or you can try upgrading to the latest version of Tor. If this works well, please help by documenting what you did, and letting us know about it.
- Tor needs some architectural changes too. One important change is to start providing better service to people who relay traffic. We're working on this, and we'll finish faster if we get to spend more time on it.
- Help do other things so we can do the hard stuff. Please take a moment to figure out what your skills and interests are, and then look at our volunteer page.
- Help find sponsors for Tor. Do you work at a company or government agency that uses Tor or has a use for Internet privacy, e.g. to browse the competition's websites discreetly, or to connect back to the home servers when on the road without revealing affiliations? If your organization has an interest in keeping the Tor network working, please contact them about supporting Tor. Without sponsors, Tor is going to become even slower.
- If you can't help out with any of the above, you can still help out individually by donating a bit of money to the cause. It adds up!
What would the Tor project do with more funding?
We have about 1500 relays right now, pushing over 150 MB/s average traffic. We have several hundred thousand active users. But the Tor network is not yet self-sustaining.
There are six main development/maintenance pushes that need attention:
- Scalability: We need to keep scaling and decentralizing the Tor architecture so it can handle thousands of relays and millions of users. The upcoming stable release is a major improvement, but there's lots more to be done next in terms of keeping Tor fast and stable.
- User support: With this many users, a lot of people are asking questions all the time, offering to help out with things, and so on. We need good clean docs, and we need to spend some effort coordinating volunteers.
- Relay support: the Tor network is run by volunteers, but they still need attention with prompt bug fixes, explanations when things go wrong, reminders to upgrade, and so on. The network itself is a commons, and somebody needs to spend some energy making sure the relay operators stay happy. We also need to work on stability on some platforms — e.g., Tor relays have problems on Win XP currently.
- Usability: Beyond documentation, we also need to work on usability of the software itself. This includes installers, clean GUIs, easy configuration to interface with other applications, and generally automating all of the difficult and confusing steps inside Tor. We've got a start on this with the GUI Contest, but much more work remains — usability for privacy software has never been easy.
- Incentives: We need to work on ways to encourage people to configure their Tors as relays and exit nodes rather than just clients. We need to make it easy to become a relay, and we need to give people incentives to do it.
- Research: The anonymous communications field is full of surprises and gotchas. In our copious free time, we also help run top anonymity and privacy conferences like PETS. We've identified a set of critical Tor research questions that will help us figure out how to make Tor secure against the variety of attacks out there. Of course, there are more research questions waiting behind these.
We're continuing to move forward on all of these, but at this rate the Tor network is growing faster than the developers can keep up. Now would be an excellent time to add a few more developers to the effort so we can continue to grow the network.
We are also excited about tackling related problems, such as censorship-resistance.
We are proud to have sponsorship and support from the Omidyar Network, the International Broadcasting Bureau, Bell Security Solutions, the Electronic Frontier Foundation, several government agencies and research groups, and hundreds of private contributors.
However, this support is not enough to keep Tor abreast of changes in the Internet privacy landscape. Please donate to the project, or contact our executive director for information on making grants or major donations.