docs/en/tor-doc-server.wml (b358ef7e9) - tor-webwml.git

tor-doc-server.wml

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#include "head.wmi" TITLE="Server Configuration Instructions"

<h1>Configuring a <a href="<page index>">Tor</a> server</h1>
<br />

<p>
The Tor network relies on volunteers to donate bandwidth. The more
people who run servers, the faster the Tor network will be. If you have
at least 20 kilobytes/s each way, please help out Tor by configuring your
Tor to be a server too. We have many features that make Tor servers easy
and convenient, including rate limiting for bandwidth, exit policies so
you can limit your exposure to abuse complaints, and support for dynamic
IP addresses.</p>

<p>Having servers in many different places on the Internet is what
makes Tor users secure. <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#ServerAnonymity">You
may also get stronger anonymity yourself</a>,
since remote sites can't know whether connections originated at your
computer or were relayed from others.</p>

<p>Setting up a Tor server is easy and convenient:
<ul>
<li>Tor has built-in support for <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#LimitBandwidth">rate
limiting</a>. Further, if you have a fast link
but want to limit the number of bytes per day
(or week or month) that you donate, check out the <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#Hibernation">hibernation
feature</a>.
</li>
<li>Each Tor server has an <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#RunAServerBut">exit
policy</a> that specifies what sort of outbound connections are allowed
or refused from that server. If you are uncomfortable allowing people
to exit from your server, you can set it up to only allow connections
to other Tor servers.
</li>
<li>It's fine if the server goes offline sometimes. The directories
notice this quickly and stop advertising the server. Just try to make
sure it's not too often, since connections using the server when it
disconnects will break.
</li>
<li>We can handle servers with dynamic IPs just fine &mdash; simply
leave the Address config option blank, and Tor will try to guess.
</li>
<li>If your server is behind a NAT and it doesn't know its public
IP (e.g. it has an IP of 192.168.x.y), you'll need to set up port
forwarding. Forwarding TCP connections is system dependent but <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#ServerForFirewalledClients">this
FAQ entry</a> offers some examples on how to do this.
</li>
<li>Your server will passively estimate and advertise its recent
bandwidth capacity, so high-bandwidth servers will attract more users than
low-bandwidth ones. Therefore having low-bandwidth servers is useful too.
</li>
</ul>

<p>You can run a Tor server on
pretty much any operating system, but see <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#ServerOS">this
FAQ entry</a> for advice about which ones work best and other problems
you might encounter.</p>

<hr />
<a id="zero"></a>
<h2><a class="anchor" href="#zero">Step Zero: Download and Install Tor</a></h2>
<br />

<p>Before you start, you need to make sure that Tor is up and running.
</p>

<p>For Windows users, this means at least <a
href="<page docs/tor-doc-win32>#installing">step one</a>
of the Windows Tor installation howto. Mac OS X users need to do at least
<a href="<page docs/tor-doc-osx>#installing">step one</a>
of OS X Tor installation howto.  Linux/BSD/Unix users should do at least
<a href="<page docs/tor-doc-unix>#installing">step one</a>
of the Unix Tor installation howto.
</p>

<p>If it's convenient, you might also want to use it as a client for a
while to make sure it's actually working.</p>

<hr />
<a id="setup"></a>
<h2><a class="anchor" href="#setup">Step One: Set it up as a server</a></h2>
<br />

<p>
1. Verify that your clock is set correctly. If possible, synchronize
your clock with public time servers.
</p>

<p>
2. Make sure name resolution works (that is, your computer can resolve
Internet addresses correctly).
</p>

<p>
3. Edit the bottom part of your torrc. (See <a
href="http://wiki.noreply.org/wiki/TheOnionRouter/TorFAQ#torrc">this
FAQ entry</a> for help.)
Make sure to define at least Nickname and ORPort. Create the DataDirectory
if necessary, and make sure it's owned by the user that will be running
tor. <em>If you want to run more than one server that's great, but
please set <a href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#MultipleServers">the
MyFamily option</a> in all your servers' configuration files.</em>
</p>

<p>
4. If you are using a firewall, open a hole in your firewall so
incoming connections can reach the ports you configured in step 3 (ORPort, plus
DirPort if you enabled it). Make sure you allow all outgoing connections,
so your server can reach the other Tor servers.
</p>

<p>
5. Restart your server. If it <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#Logs">logs
any warnings</a>, address them.
</p>

<p>
6. Subscribe to the <a
href="http://archives.seul.org/or/announce/">or-announce</a>
mailing list. It is very low volume, and it will keep you informed
of new stable releases. You might also consider subscribing to <a
href="http://archives.seul.org/or/talk/">or-talk</a> (higher volume),
where new development releases are announced.
</p>

<p>
7. Have a look at the manual.
The <a href="<page tor-manual>">manual</a> for the
latest stable version provides a list of all the possible configuration
options for both clients and servers.
If you are running the development version of Tor, the manual is available
<a href="<page tor-manual-dev>">here</a>.
</p>

<hr />
<a id="check"></a>
<h2><a class="anchor" href="#check">Step Two: Make sure it's working</a></h2>
<br />

<p>As soon as your server manages to connect to the network, it will
try to determine whether the ports you configured are reachable from
the outside. This may take up to 20 minutes. Look for a
<a href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#Logs">log
entry</a> like
<tt>Self-testing indicates your ORPort is reachable from the outside. Excellent.</tt>
If you don't see this message, it means that your server is not reachable
from the outside &mdash; you should re-check your firewalls, check that it's
testing the IP and port you think it should be testing, etc.
</p>

<p>When it decides that it's reachable, it will upload a "server
descriptor" to the directories. This will let clients know
what address, ports, keys, etc your server is using. You can <a
href="http://moria.seul.org:9032/tor/status/authority">load one of
the network statuses manually</a> and
look through it to find the nickname you configured, to make sure it's
there. You may need to wait a few seconds to give enough time for it to
make a fresh directory.</p>

<hr />
<a id="after"></a>
<h2><a class="anchor" href="#after">Step Three: Once it's working</a></h2>
<br />

<p>
We recommend the following steps as well:
</p>

<p>
8. Read
<a href="http://wiki.noreply.org/noreply/TheOnionRouter/OperationalSecurity">this document</a>
to get ideas how you can increase the security of your server.
</p>

<p>
9. Decide what exit policy you want. By default your server allows
access to many popular services, but restricts some (such as port 25)
due to abuse potential. You might want an exit policy that is
less restrictive or more restrictive; edit your torrc appropriately.
Read the FAQ entry on <a
href="<page faq-abuse>#TypicalAbuses">issues you might
encounter if you use the default exit policy</a>.
If you choose a particularly open exit policy, you should make
sure your ISP is ok with that choice.
If there are any resources that your computer can't reach (for example,
you are behind a restrictive firewall or content filter), please
explicitly reject them in your exit policy &mdash; otherwise Tor users
will be impacted too.
</p>

<p>
10. Decide about rate limiting. Cable modem, DSL, and other users
who have asymmetric bandwidth (e.g. more down than up) should
rate limit to their slower bandwidth, to avoid congestion. See the <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#LimitBandwidth">rate
limiting FAQ entry</a> for details.
</p>

<p>
11. Back up your Tor server's private key (stored in "keys/secret_id_key"
in your DataDirectory). This is your server's "identity," and
you need to keep it safe so nobody can read the traffic that goes
through your server. This is the critical file to keep if you need to <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#UpgradeServer">move
or restore your Tor server</a> if something goes wrong.
</p>

<p>
12. If you control the name servers for your domain, consider setting
your hostname to 'anonymous' or 'proxy' or 'tor-proxy', so when other
people see the address in their web logs, they will more quickly
understand what's going on.
</p>

<p>
13. If your computer isn't running a webserver, please consider
changing your ORPort to 443 and your DirPort to 80. Many Tor
users are stuck behind firewalls that only let them browse the
web, and this change will let them reach your Tor server. Win32
servers can simply change their ORPort and DirPort directly
in their torrc and restart Tor. OS X or Unix servers can't bind
directly to these ports (since they don't run as root), so they will
need to set up some sort of <a
href="http://wiki.noreply.org/wiki/TheOnionRouter/TorFAQ#ServerForFirewalledClients">
port forwarding</a> so connections can reach their Tor server. If you are
using ports 80 and 443 already but still want to help out, other useful
ports are 22, 110, and 143.
</p>

<p>
14. If your Tor server provides other services on the same IP address
&mdash; such as a public webserver &mdash; make sure that connections to the
webserver are allowed from the local host too. You need to allow these
connections because Tor clients will detect that your Tor server is the <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#ExitEavesdroppers">safest
way to reach that webserver</a>, and always build a circuit that ends
at your server. If you don't want to allow the connections, you must
explicitly reject them in your exit policy.
</p>

<p>
15. (Unix only). Make a separate user to run the server. If you
installed the OS X package or the deb or the rpm, this is already
done. Otherwise, you can do it by hand. (The Tor server doesn't need to
be run as root, so it's good practice to not run it as root. Running
as a 'tor' user avoids issues with identd and other services that
detect user name. If you're the paranoid sort, feel free to <a
href="http://wiki.noreply.org/wiki/TheOnionRouter/TorInChroot">put Tor
into a chroot jail</a>.)
</p>

<p>
16. (Unix only.) Your operating system probably limits the number
of open file descriptors per process to 1024 (or even less). If you
plan to be running a fast exit node, this is probably not enough. On
Linux, you should add a line like "toruser hard nofile 8192" to your
/etc/security/limits.conf file (where toruser is the user that runs the
Tor process), and then restart Tor if it's installed as a package (or log
out and log back in if you run it yourself). If that doesn't work, see <a
href="http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#FileDescriptors">this
FAQ entry</a> for other suggested ways to run "ulimit -n 8192" before
you launch Tor.
</p>

<p>
17. If you installed Tor via some package or installer, it probably starts
Tor for you automatically on boot. But if you installed from source,
you may find the initscripts in contrib/tor.sh or contrib/torctl useful.
</p>

<p>
When you change your Tor configuration, remember to verify that your
server still works correctly after the change. Be sure to set your
"ContactInfo" line in the torrc so we can contact you if you need to
upgrade or something goes wrong. If you have problems or questions, see
the <a href="<page documentation>#Support">Support</a> section or
<a href="<page contact>">contact us</a> on the tor-ops list. Thanks
for helping to make the Tor network grow!
</p>

<hr />

<p>If you have suggestions for improving this document, please <a
href="<page contact>">send them to us</a>. Thanks!</p>

</div>
</div>

#include <foot.wmi>

tor-webwml.git

Clarify which ports we mean in step 4 of server configuration. This probably won't please the fellow who complained back in August, but it does let me remove his email from my =todo folder in good conscience.