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    <a href="<page index>">Home &raquo; </a>
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    <a href="<page docs/faq-abuse>">Abuse FAQ</a>
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  <div id="maincol"> 
    
    <h1>Abuse FAQ</h1>
    #
    #<div class="sidebar-left">
    #<h3>Questions</h3>
    #<ul>
    #<li><a href="<page docs/faq-abuse>#WhatAboutCriminals">Doesn't Tor enable criminals to do bad things?</a></li>
    #<li><a href="<page docs/faq-abuse>#DDoS">What about distributed denial of service attacks?</a></li>
    #<li><a href="<page docs/faq-abuse>#WhatAboutSpammers">What about spammers?</a></li>
    #<li><a href="<page docs/faq-abuse>#HowMuchAbuse">Does Tor get much abuse?</a></li>
    #<li><a href="<page docs/faq-abuse>#TypicalAbuses">So what should I expect if I run an exit relay?</a></li>
    #<li><a href="<page docs/faq-abuse>#IrcBans">Tor is banned from the IRC network I want to use.</a></li>
    #<li><a href="<page docs/faq-abuse>#SMTPBans">Your nodes are banned from the mail server I want to use.</a></li>
    #<li><a href="<page docs/faq-abuse>#Bans">I want to ban the Tor network from my service.</a></li>
    #<li><a href="<page docs/faq-abuse>#TracingUsers">I have a compelling reason to trace a Tor user. Can you help?</a></li>
    #<li><a href="<page docs/faq-abuse>#RemoveContent">I want some content removed from a .onion address.</a></li>
    #<li><a href="<page docs/faq-abuse>#LegalQuestions">I have legal questions about Tor abuse.</a></li>
    #</ul>
    #</div>
    #
    #<hr />
    
    <a id="WhatAboutCriminals"></a>
    <h3><a class="anchor" href="#WhatAboutCriminals">Doesn't Tor enable criminals to do bad things?</a></h3>
    
    <p>Criminals can already do bad things. Since they're willing to
    break laws, they already have lots of options available that provide
    <em>better</em> privacy than Tor provides. They can steal cell phones,
    use them, and throw them in a ditch; they can crack into computers
    in Korea or Brazil and use them to launch abusive activities; they
    can use spyware, viruses, and other techniques to take control of
    literally millions of Windows machines around the world. </p>
    
    <p>Tor aims to provide protection for ordinary people who want to follow
    the law. Only criminals have privacy right now, and we need to fix that. </p>
    
    <p>Some advocates of anonymity explain that it's just a tradeoff &mdash;
    accepting the bad uses for the good ones &mdash; but there's more to it
    than that.
    Criminals and other bad people have the motivation to learn how to
    get good anonymity, and many have the motivation to pay well to achieve
    it. Being able to steal and reuse the identities of innocent victims
    (identify theft) makes it even easier. Normal people, on the other hand,
    don't have the time or money to spend figuring out how to get
    privacy online. This is the worst of all possible worlds. </p>
    
    <p>So yes, criminals could in theory use Tor, but they already have
    better options, and it seems unlikely that taking Tor away from the
    world will stop them from doing their bad things. At the same time, Tor
    and other privacy measures can <em>fight</em> identity theft, physical
    crimes like stalking, and so on. </p>
    
    
    
    <a id="DDoS"></a>
    <h3><a class="anchor" href="#DDoS">What about distributed denial of service attacks?</a></h3>
    
    <p>Distributed denial of service (DDoS) attacks typically rely on having a group
    of thousands of computers all sending floods of traffic to a victim. Since
    the goal is to overpower the bandwidth of the victim, they typically send
    UDP packets since those don't require handshakes or coordination. </p>
    
    <p>But because Tor only transports correctly formed TCP streams, not
    all IP packets, you cannot send UDP packets over Tor. (You can't do
    specialized forms of this attack like SYN flooding either.) So ordinary
    DDoS attacks are not possible over Tor. Tor also doesn't allow bandwidth
    amplification attacks against external sites: you need to send in a byte
    for every byte that the Tor network will send to your destination. So
    in general, attackers who control enough bandwidth to launch an effective
    DDoS attack can do it just fine without Tor. </p>
    
    <a id="WhatAboutSpammers"></a>
    <h3><a class="anchor" href="#WhatAboutSpammers">What about spammers?</a></h3>
    
    <p>First of all, the default Tor exit policy rejects all outgoing
    port 25 (SMTP) traffic. So sending spam mail through Tor isn't going to
    work by default. It's possible that some relay operators will enable
    port 25 on their particular exit node, in which case that computer will
    allow outgoing mails; but that individual could just set up an open mail
    relay too, independent of Tor. In short, Tor isn't useful for spamming,
    because nearly all Tor relays refuse to deliver the mail. </p>
    
    <p>Of course, it's not all about delivering the mail. Spammers can use
    Tor to connect to open HTTP proxies (and from there to SMTP servers); to
    connect to badly written mail-sending CGI scripts; and to control their
    botnets &mdash; that is, to covertly communicate with armies of
    compromised computers that deliver the spam.
    </p>
    
    <p>
    This is a shame, but notice that spammers are already doing great
    without Tor. Also, remember that many of their more subtle communication
    mechanisms (like spoofed UDP packets) can't be used over Tor, because
    it only transports correctly-formed TCP connections.
    </p>
    
    <a id="ExitPolicies"></a>
    <h3><a class="anchor" href="#ExitPolicies">How do Tor exit policies work?</a></h3>
    
    <p>
    <a href="<wiki>TorFAQ#ExitPolicies">See the FAQ</a>
    </p>
    
    <a id="HowMuchAbuse"></a>
    <h3><a class="anchor" href="#HowMuchAbuse">Does Tor get much abuse?</a></h3>
    
    <p>Not much, in the grand scheme of things. We've been running the network
    since October 2003, and it's only generated a handful of complaints. Of
    course, like all privacy-oriented networks on the net, we attract our
    share of jerks. Tor's exit policies help separate the role of "willing
    to donate resources to the network" from the role of "willing to deal
    with exit abuse complaints," so we hope our network is more sustainable
    than past attempts at anonymity networks. </p>
    
    <p>Since Tor has
    <a href="<page about/overview>">many good uses as
    well</a>, we feel that we're doing pretty well at striking a balance
    currently. </p>
    
    <a id="TypicalAbuses"></a>
    <h3><a class="anchor" href="#TypicalAbuses">So what should I expect if I run an exit relay?</a></h3>
    
    <p>If you run a Tor relay that allows exit connections (such as the
    default exit policy), it's probably safe to say that you will eventually
    hear from somebody. Abuse
    complaints may come in a variety of forms. For example: </p>
    <ul>
    <li>Somebody connects to Hotmail, and sends a ransom note to a
    company. The
    FBI sends you a polite email, you explain that you run a Tor relay,
    and they say "oh well" and leave you alone. [Port 80]</li>
    <li>Somebody tries to get you shut down by using Tor to connect to Google
    groups and post spam to Usenet, and then sends an angry mail to
    your ISP about how you're destroying the world. [Port 80]</li>
    <li>Somebody connects to an IRC network and makes a nuisance of
    himself. Your ISP gets polite mail about how your computer has been
    compromised; and/or your computer gets DDoSed. [Port 6667]</li>
    <li>Somebody uses Tor to download a Vin Diesel movie, and
    your ISP gets a DMCA takedown notice. See EFF's
    <a href="<page eff/tor-dmca-response>">Tor DMCA Response
    Template</a>, which explains why your ISP can probably ignore
    the notice without any liability. [Arbitrary ports]</li>
    </ul>
    
    <p>You might also find that your Tor relay's IP is blocked from accessing
    some Internet sites/services. This might happen regardless of your exit
    policy, because some groups don't seem to know or care that Tor has
    exit policies. (If you have a spare IP not used for other activities,
    you might consider running your Tor relay on it.) For example, </p>
    
    <ul>
    <li>Because of a few cases of anonymous jerks messing with its web
    pages, Wikipedia is currently blocking many Tor relay IPs from writing
    (reading still works). We're talking to Wikipedia about how they might
    control abuse while still providing access to anonymous contributors,
    who often have hot news or inside info on a topic but don't want to risk
    revealing their identities when publishing it (or don't want to reveal
    to local observers that they're accessing Wikipedia). Slashdot is also
    in the same boat.</li>
    
    <li>SORBS is putting some Tor relay IPs on their email
    blacklist as well. They do this because they passively detect whether your
    relay connects to certain IRC networks, and they conclude from this that
    your relay is capable of spamming. We tried to work with
    them to teach them that not all software works this way,
    but we have given up. We recommend you avoid them, and <a
    href="http://paulgraham.com/spamhausblacklist.html">teach your friends
    (if they use them) to avoid abusive blacklists too</a>.</li>
    
    </ul>
    
    <a id="IrcBans"></a>
    <h3><a class="anchor" href="#IrcBans">Tor is banned from the IRC network I want to use.</a></h3>
    
    <p>Sometimes jerks make use of Tor to troll IRC channels. This abuse
    results in IP-specific temporary bans ("klines" in IRC lingo), as the
    network operators try to keep the troll off of their network. </p>
    
    <p>This response underscores a fundamental flaw in IRC's security model:
    they assume that IP addresses equate to humans, and by banning the
    IP address they can ban the human. In reality this is not the case &mdash;
    many such trolls routinely make use of the literally millions of open
    proxies and compromised computers around the Internet. The IRC networks
    are fighting a losing battle of trying to block all these nodes,
    and an entire cottage industry of blacklists and counter-trolls has
    sprung up based on this flawed security model (not unlike the antivirus
    industry). The Tor network is just a drop in the bucket here. </p>
    
    <p>On the other hand, from the viewpoint of IRC server operators, security
    is not an all-or-nothing thing.  By responding quickly to trolls or
    any other social attack, it may be possible to make the attack scenario
    less attractive to the attacker.  And most individual IP addresses do
    equate to individual humans, on any given IRC network at any given time.
    The exceptions include NAT gateways which may be allocated access as
    special cases. While it's a losing battle to try to stop the use of open
    proxies, it's not generally a losing battle to keep klining a single
    ill-behaved IRC user until that user gets bored and goes away. </p>
    
    <p>But the real answer is to implement application-level auth systems,
    to let in well-behaving users and keep out badly-behaving users. This
    needs to be based on some property of the human (such as a password he
    knows), not some property of the way his packets are transported. </p>
    
    <p>Of course, not all IRC networks are trying to ban Tor nodes. After
    all, quite a few people use Tor to IRC in privacy in order to carry
    on legitimate communications without tying them to their real-world
    identity. Each IRC network needs to decide for itself if blocking a few
    more of the millions of IPs that bad people can use is worth losing the
    contributions from the well-behaved Tor users. </p>
    
    <p>If you're being blocked, have a discussion with the network operators
    and explain the issues to them. They may not be aware of the existence of
    Tor at all, or they may not be aware that the hostnames they're klining
    are Tor exit nodes.  If you explain the problem, and they conclude that
    Tor ought to be blocked, you may want to consider moving to a network that
    is more open to free speech.  Maybe inviting them to #tor on irc.oftc.net
    will help show them that we are not all evil people. </p>
    
    <p>Finally, if you become aware of an IRC network that seems to be
    blocking Tor, or a single Tor exit node, please put that information on <a
    href="https://wiki.torproject.org/wiki/TheOnionRouter/BlockingIrc">The Tor
    IRC block tracker</a>
    so that others can share.  At least one IRC network consults that page
    to unblock exit nodes that have been blocked inadvertently. </p>
    
    <a id="SMTPBans"></a>
    <h3><a class="anchor" href="#SMTPBans">Your nodes are banned from the mail server I want to use.</a></h3>
    
    <p>Even though <a href="#WhatAboutSpammers">Tor isn't useful for
    spamming</a>, some over-zealous blacklisters seem to think that all
    open networks like Tor are evil &mdash; they attempt to strong-arm network
    administrators on policy, service, and routing issues, and then extract
    ransoms from victims. </p>
    
    <p>If your server administrators decide to make use of these
    blacklists to refuse incoming mail, you should have a conversation with
    them and explain about Tor and Tor's exit policies. </p>
    
    <a id="Bans"></a>
    <h3><a class="anchor" href="#Bans">I want to ban the Tor network from my service.</a></h3>
    
    <p>We're sorry to hear that. There are some situations where it makes
    sense to block anonymous users for an Internet service. But in many
    cases, there are easier solutions that can solve your problem while
    still allowing users to access your website securely.</p>
    
    <p>First, ask yourself if there's a way to do application-level decisions
    to separate the legitimate users from the jerks. For example, you might
    have certain areas of the site, or certain privileges like posting,
    available only to people who are registered. It's easy to build an
    up-to-date list of Tor IP addresses that allow connections to your
    service, so you could set up this distinction only for Tor users. This
    way you can have multi-tiered access and not have to ban every aspect
    of your service. </p>
    
    <p>For example, the <a
    href="http://freenode.net/policy.shtml#tor">Freenode IRC network</a>
    had a problem with a coordinated group of abusers joining channels and
    subtly taking over the conversation; but when they labelled all users
    coming from Tor nodes as "anonymous users," removing the ability of the
    abusers to blend in, the abusers moved back to using their open proxies
    and bot networks. </p>
    
    <p>Second, consider that hundreds of thousands of
    people use Tor every day simply for
    good data hygiene &mdash; for example, to protect against data-gathering
    advertising companies while going about their normal activities. Others
    use Tor because it's their only way to get past restrictive local
    firewalls. Some Tor users may be legitimately connecting
    to your service right now to carry on normal activities. You need to
    decide whether banning the Tor network is worth losing the contributions
    of these users, as well as potential future legitimate users. (Often
    people don't have a good measure of how many polite Tor users are
    connecting to their service &mdash; you never notice them until there's
    an impolite one.)</p>
    
    <p>At this point, you should also ask yourself what you do about other
    services that aggregate many users behind a few IP addresses. Tor is
    not so different from AOL in this respect.</p>
    
    <p>Lastly, please remember that Tor relays have <a
    href="<wiki>#ExitPolicies">individual exit policies</a>. Many Tor relays do
    not allow exiting connections at all. Many of those that do allow some
    exit connections might already disallow connections to
    your service. When you go about banning nodes, you should parse the
    exit policies and only block the ones that allow these connections;
    and you should keep in mind that exit policies can change (as well as
    the overall list of nodes in the network).</p>
    
    <p>If you really want to do this, we provide a
    <a href="https://check.torproject.org/cgi-bin/TorBulkExitList.py">Tor
    exit relay list</a> or a
    <a href="<page projects/tordnsel>">DNS-based list you can query</a>.
    </p>
    
    <p>
    (Some system administrators block ranges of IP addresses because of
    official policy or some abuse pattern, but some have also asked about
    whitelisting Tor exit relays because they want to permit access to their
    systems only using Tor. These scripts are usable for whitelisting as well.)
    </p>
    
    <a id="TracingUsers"></a>
    <h3><a class="anchor" href="#TracingUsers">I have a compelling reason to trace a Tor user. Can you help?</a></h3>
    
    <p>
    There is nothing the Tor developers can do to trace Tor users. The same
    protections that keep bad people from breaking Tor's anonymity also
    prevent us from figuring out what's going on.
    </p>
    
    <p>
    Some fans have suggested that we redesign Tor to include a <a
    href="<wikifaq>#Backdoor">backdoor</a>.
    There are two problems with this idea. First, it technically weakens the
    system too far. Having a central way to link users to their activities
    is a gaping hole for all sorts of attackers; and the policy mechanisms
    needed to ensure correct handling of this responsibility are enormous
    and unsolved. Second, the bad people <a href="#WhatAboutCriminals">aren't
    going to get caught by this anyway</a>, since they will use other means
    to ensure their anonymity (identity theft, compromising computers and
    using them as bounce points, etc).
    </p>
    
    <p>
    But remember that this doesn't mean that Tor is invulnerable. Traditional
    police techniques can still be very effective against Tor, such as
    interviewing suspects, surveillance and keyboard taps, writing style
    analysis, sting operations, and other physical investigations.
    </p>
    
    <a id="RemoveContent"></a>
    <h3><a class="anchor" href="#RemoveContent">I want some content removed from a .onion address.</a></h3>
    <p>The Tor Project does not host, control, nor have the ability to
    discover the owner or location of a .onion address.  The .onion address is
    an address from <a href="<page docs/hidden-services>">a hidden
    service</a>.  The name you see ending in .onion is a hidden service descriptor.
    It's an automatically generated name which can be located on any Tor
    relay or client anywhere on the Internet.  Hidden services are designed
    to protect both the user and service provider from discovering who they
    are and where they are from.  The design of hidden services means the
    owner and location of the .onion site is hidden even from us.</p>
    <p>But remember that this doesn't mean that hidden services are
    invulnerable. Traditional police techniques can still be very effective
    against them, such as interviewing suspects, surveillance and keyboard
    taps, writing style analysis, sting operations, and other physical
    investigations.</p>
    <p>If you have a complaint about child pornography, you may wish to report
    it to the National Center for Missing and Exploited Children, which serves
    as a national coordination point for investigation of child pornography:
    <a href="http://www.missingkids.com/">http://www.missingkids.com/</a>.
    We do not view links you report.</p>
    
    <a id="LegalQuestions"></a>
    <h3><a class="anchor" href="#LegalQuestions">I have legal questions about Tor abuse.</a></h3>
    
    <p>We're only the developers. We can answer technical questions, but
    we're not the ones to talk to about legal questions or concerns. </p>
    
    <p>Please take a look at the
    <a href="<page eff/tor-legal-faq>">Tor Legal FAQ</a>,
    and contact EFF directly if you have any further legal questions. </p>
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