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tor-onion-service.wml

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#include "head.wmi" TITLE="Tor Project: Onion Service Configuration Instructions" CHARSET="UTF-8"
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    <a href="<page index>">Home &raquo; </a>
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    <h1>Configuring Onion Services for <a href="<page index>">Tor</a></h1>

<hr />

<p>Tor allows clients and relays to offer onion services. That is,
    you can offer a web server, SSH server, etc., without revealing your
    IP address to its users. In fact, because you don't use any public address,
    you can run an onion service from behind your firewall.
    </p>

<p>If you have Tor installed, you can see onion services in action
    by visiting this <a href="http://duskgytldkxiuqc6.onion/">sample
    site</a>.
    </p>

<p>
    This page describes the steps for setting up your own onion service
    website. For the technical details of how the onion service protocol
    works, see our <a href="<page docs/onion-services>">onion service
    protocol</a> page.
    </p>

<hr>
    <ul>
      <li><a href="#zero">Step Zero: Get Tor working</a></li>
      <li><a href="#one">Step One: Install a web server locally</a></li>
      <li><a href="#two">Step Two: Configure your onion service</a></li>
      <li><a href="#three">Step Three: More advanced tips</a></li>
      <li><a href="#four">Step Four: Set up next-gen (v3) onions</a></li>
    </ul>
    <hr>

<a id="zero"></a>
    <h2><a class="anchor" href="#zero">Step Zero: Get Tor working</a></h2>
    <br>

<p>Before you start, you need to make sure:</p>
    <ol>
    <li>Tor is up and running,</li>
    <li>You actually set it up correctly.</li>
    </ol>

<p>Windows users should follow the <a
    href="<page docs/tor-doc-windows>">Windows
    howto</a>, OS X users should follow the <a
    href="<page docs/tor-doc-osx>">OS
    X howto</a>, and Linux/BSD/Unix users should follow the <a
    href="<page docs/tor-doc-unix>">Unix howto</a>.
    </p>

<hr>
    <a id="one"></a>
    <h2><a class="anchor" href="#one">Step One: Install a web server locally</a></h2>
    <br>

<p>
    First, you need to set up a web server locally, for example nginx or
    lighttpd (apache is not the best option for anomymity, see
    <a href="#three">Step Three</a> below).
    Setting up a web server can be complex. We're not going to cover how to set
    up a web server here. If you get stuck or want to do more, find a friend who
    can help you. We recommend you install a new separate web server for
    your onion service, since even if you already have one installed,
    you may be using it (or want to use it later) for a normal website.
    </p>

<p>
    You need to configure your web server so it doesn't give away any
    information about you, your computer, or your location. Be sure to
    bind the web server only to localhost (if people could get to it
    directly, they could confirm that your computer is the one offering
    the onion service). Be sure that its error messages don't list
    your hostname or other hints. Consider putting the web server in a
    sandbox or VM to limit the damage from code vulnerabilities.
    </p>

<p>
    Once your web server is set up, make
    sure it works: open your browser and go to <a
    href="http://localhost:8080/">http://localhost:8080/</a>, where
    8080 is the webserver port you chose during setup (you can choose any
    port, 8080 is just an example). Then try putting a file in the main
    html directory, and make sure it shows up when you access the site.
    </p>

<hr>
    <a id="two"></a>
    <h2><a class="anchor" href="#two">Step Two: Configure your onion service</a></h2>
    <br>

<p>Next, you need to configure your onion service to point to your
    local web server.
    </p>

<p>First, open your torrc file in your favorite text editor. (See
    <a href="<page docs/faq>#torrc">the torrc FAQ entry</a> to learn
    what this means.) Go to the middle section and look for the line</p>

<pre>
    \############### This section is just for location-hidden services ###
    </pre>

<p>
    This section of the file consists of groups of lines, each representing
    one onion service. Right now they are all commented out (the lines
    start with #), so onion services are disabled. Each group of lines
    consists of one <var>HiddenServiceDir</var> line, and one or more
    <var>HiddenServicePort</var> lines:</p>
    <ul>
	<li><var>HiddenServiceDir</var> is a directory where Tor will store
	information about that onion service.  In particular, Tor will create a
	file here named <var>hostname</var> which will tell you the onion URL.  You
	don't need to add any files to this directory. Make sure this is not the
	same directory as the hidserv directory you created when setting up thttpd,
	as your HiddenServiceDir contains secret information!</li>
	<li><var>HiddenServicePort</var> lets you specify a virtual port (that is,
	what port people accessing the onion service will think they're using) and
	an IP address and port for redirecting connections to this virtual
	port.</li> </ul>

<p>Add the following lines to your torrc:
    </p>

<pre>
    HiddenServiceDir /Library/Tor/var/lib/tor/hidden_service/
    HiddenServicePort 80 127.0.0.1:8080
    </pre>

<p>You're going to want to change the <var>HiddenServiceDir</var> line, so
	it points to an actual directory that is readable/writeable by the user
	that will be running Tor. The above line should work if you're using the OS
	X Tor package. On Unix, try "/home/username/hidden_service/" and fill in
	your own username in place of "username". On Windows you might pick:</p>
	<pre> HiddenServiceDir C:\Users\username\Documents\tor\hidden_service
	HiddenServicePort 80 127.0.0.1:8080 </pre>

<p>Note that since 0.2.6, both <var>SocksPort</var> and <var>HiddenServicePort</var>
    support Unix sockets. This means that you can point the <var>HiddenServicePort</var>
    to a Unix socket:</p>
    <pre>
    HiddenServiceDir /Library/Tor/var/lib/tor/hidden_service/
    HiddenServicePort 80 unix:/path/to/socket
    </pre>

<p>Now save the torrc and restart your tor.</p>

<p>If Tor starts up again, great. Otherwise, something is wrong. First look
	at your logfiles for hints. It will print some warnings or error messages.
	That should give you an idea what went wrong. Typically there are typos in
	the torrc or wrong directory permissions (See <a href="<page
	docs/faq>#Logs">the logging FAQ entry</a> if you don't know how to enable
	or find your log file.) </p>

<p>When Tor starts, it will automatically create the
	<var>HiddenServiceDir</var> that you specified (if necessary), and it will
	create two files there.</p>

<dl>
    <dt><var>private_key</var></dt>
    <dd>First, Tor will generate a new public/private keypair for your onion
    service. It is written into a file called "private_key". Don't share this key
    with others -- if you do they will be able to impersonate your onion
    service.</dd>
    <dt><var>hostname</var></dt>
    <dd>The other file Tor will create is called "hostname". This contains
    a short summary of your public key -- it will look something like
    <tt>duskgytldkxiuqc6.onion</tt>. This is the public name for your service,
    and you can tell it to people, publish it on websites, put it on business
    cards, etc.</dd>
    </dl>

<p>If Tor runs as a different user than you, for example on
    OS X, Debian, or Red Hat, then you may need to become root to be able
    to view these files.</p>

<p>Now that you've restarted Tor, it is busy picking introduction points
    in the Tor network, and generating an <em>onion service
    descriptor</em>. This is a signed list of introduction points along with
    the service's full public key. It anonymously publishes this descriptor
    to the directory servers, and other people anonymously fetch it from the
    directory servers when they're trying to access your service.
    </p>

<p>Try it now: paste the contents of the hostname file into your web
    browser. If it works, you'll get the html page you set up in step one.
    If it doesn't work, look in your logs for some hints, and keep playing
    with it until it works.
    </p>

<hr>
    <a id="three"></a>
    <h2><a class="anchor" href="#three">Step Three: More advanced tips</a></h2>
    <br>

<p>If you plan to keep your service available for a long time, you might
    want to make a backup copy of the <var>private_key</var> file somewhere.
    </p>

<p>If you want to forward multiple virtual ports for a single onion
    service, just add more <var>HiddenServicePort</var> lines.
    If you want to run multiple onion services from the same Tor
    client, just add another <var>HiddenServiceDir</var> line. All the following
    <var>HiddenServicePort</var> lines refer to this <var>HiddenServiceDir</var>
    line, until you add another <var>HiddenServiceDir</var> line:
    </p>

<pre>
    HiddenServiceDir /usr/local/etc/tor/hidden_service/
    HiddenServicePort 80 127.0.0.1:8080

HiddenServiceDir /usr/local/etc/tor/other_hidden_service/
    HiddenServicePort 6667 127.0.0.1:6667
    HiddenServicePort 22 127.0.0.1:22
    </pre>

To set up an onion service on Raspbian have a look at Alec Muffett's
    <a href="https://github.com/alecmuffett/eotk">Enterprise Onion Toolkit</a>.

<p>Onion services operators need to practice proper
    <a href="https://trac.torproject.org/projects/tor/wiki/doc/OperationalSecurity">
    operational security</a> and system administration to maintain security.
    For some security suggestions please make sure you read over Riseup's
    <a href="https://help.riseup.net/en/security/network-security/tor/onionservices-best-practices">
    "Tor Hidden (Onion) Services Best Practices" document</a>.
    Also, here are some more anonymity issues you should keep in mind:
    </p>
    <ul>
    <li>As mentioned above, be careful of letting your web server reveal
    identifying information about you, your computer, or your location.
    For example, readers can probably determine whether it's thttpd or
    Apache, and learn something about your operating system.</li>
    <li>If your computer isn't online all the time, your onion service
    won't be either. This leaks information to an observant adversary.</li>
    <li>It is generally a better idea to host onion services on a Tor client
    rather than a Tor relay, since relay uptime and other properties are
    publicly visible.</li>
    <li>The longer an onion service is online, the higher the risk that its
    location is discovered. The most prominent attacks are building a
    profile of the onion service's availability and matching induced
    traffic patterns.</li>
    </ul>

<p>Another common issue is whether to use HTTPS on your relay or
    not. Have a look at this <a
    href="https://blog.torproject.org/blog/facebook-hidden-services-and-https-certs">post</a>
    on the Tor Blog to learn more about these issues.
    </p>

<p>You can use <a href="https://stem.torproject.org">stem</a> to
    <a href="https://stem.torproject.org/tutorials/over_the_river.html">
    automate the management of your onion services</a>.
    </p>

<p>Finally, feel free to use the <a
    href="https://lists.torproject.org/pipermail/tor-onions/">[tor-onions]
    mailing list</a> to discuss the secure administration and operation of
    Tor onion services.</p>

<hr>
    <a id="four"></a>
    <h2><a class="anchor" href="#four">Step Four: Set up next-gen (v3) onions</a></h2>
    <br>

<p>Since Tor 0.3.2 and
    <a href="https://blog.torproject.org/tor-browser-75a5-released">Tor Browser
    7.5.a5</a> 56 bit long v3 onion addresses are supported and should be used
    instead. This newer version of onion services ("v3") features many
    improvements over the legacy system:
    </p>
    <ul>
      <li>Better crypto (replaced SHA1/DH/RSA1024 with SHA3/ed25519/curve25519)</li>
      <li>Improved directory protocol, leaking much less information to directory servers.</li>
      <li>Improved directory protocol, with smaller surface for targeted attacks.</li>
      <li>Better onion address security against impersonation.</li>
      <li>More extensible introduction/rendezvous protocol.</li>
      <li>A cleaner and more modular codebase.</li>
    </ul>
    <p>For details see
    <a href="https://trac.torproject.org/projects/tor/wiki/doc/HiddenServiceNames">
    Why are v3 onions better?</a>. You can identify a next-generation onion
    address by its length: they are 56 characters long, as in
    <var>4acth47i6kxnvkewtm6q7ib2s3ufpo5sqbsnzjpbi7utijcltosqemad.onion</a>.
    
    The specification for next gen onion services can be found
    <a href="https://gitweb.torproject.org/torspec.git/tree/rend-spec-v3.txt">
    here</a>.
    </p>

<h3>How to setup your own prop224 service</h3>

<p>It's easy! Just use your <a href"#two">regular onion service</a> torrc
    and add <var>HiddenServiceVersion 3</var> in your onion service torrc block.
    Here is an example torrc designed for testing:
    </p>
    <pre>
SocksPort auto

HiddenServiceDir /home/user/tmp/hsv3
HiddenServiceVersion 3
HiddenServicePort 6667 127.0.0.1:6667
    </pre>
    <p>Then your onion address is in <var>/home/user/tmp/hsv3/hostname</var>.
    To host both a v2 and a v3 service using two onion service torrc blocks:
    </p>
    <pre>
HiddenServiceDir /home/user/tmp/hsv2
HiddenServicePort 6667 127.0.0.1:6667

HiddenServiceDir /home/user/tmp/hsv3
HiddenServiceVersion 3
HiddenServicePort 6668 127.0.0.1:6667
    </pre>

<p>Please note that tor is strict about directory permissions and does not
    like to share its files. Make sure to restrict read and write access to the
    onion services directory before restarting tor. For most linux based systems you can use:
    </p>
    <pre>chmod 700 -R /var/lib/tor</pre>

<p>To restart tor it's safer to not use SIGHUP directly (see bug
    <a href="https://trac.torproject.org/projects/tor/ticket/21818">#21818</a>),
    but to check the validity of the config first. On Debian based systems the
    services management tool does this for you:</p>
    <pre>
    service tor restart
    </pre>

<h3>How to help the next-gen onion development</h3>

<p>Please let us know if you find any bugs!
    We are still in testing & development stage so things are very liquid and
    in active development. If you want to help with development, check out the list of
    <a href="https://trac.torproject.org/projects/tor/query?status=!closed&keywords=~prop224&order=priority">
    open prop224 bugs</a>.
    </p>

<p>For researchers our wiki page
    <a href="https://trac.torproject.org/projects/tor/wiki/doc/OnionServiceNamingSystems">
    Onion Service Naming Systems</a> could be of value. If you are more of the bug
    hunting type, please check our code and spec for errors and inaccuracies.
    We would be thrilled to know about them!
    </p>

<p>For debugging and to send us more helpful log files, turn on info logging:
    </p>
    <pre>
SafeLogging 0
Log notice file /home/user/tmp/hs/hs.log
Log info file /home/user/tmp/hs/hsinfo.log
    </pre>

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onion services: add link to Alec Muffett's Enterprise Onion Toolkit