Provided by: tor_0.1.0.16-1ubuntu2_i386 bug

NAME

       tor - The second-generation onion router

SYNOPSIS

       tor [OPTION value]...

DESCRIPTION

       tor  is  a connection-oriented anonymizing communication service. Users
       choose a source-routed path through a set of  nodes,  and  negotiate  a
       "virtual  circuit"  through  the  network, in which each node knows its
       predecessor and successor, but no  others.  Traffic  flowing  down  the
       circuit is unwrapped by a symmetric key at each node, which reveals the
       downstream node.

       Basically  tor  provides  a  distributed  network  of  servers  ("onion
       routers"). Users bounce their TCP streams -- web traffic, ftp, ssh, etc
       -- around the routers, and recipients, observers, and even the  routers
       themselves have difficulty tracking the source of the stream.

OPTIONS

       -h, -help Display a short help message and exit.

       -f FILE
              FILE   contains   further   "option   value"   pairs.  (Default:
              /etc/tor/torrc)

       Other options can be specified either on the command-line (--option
              value), or in the configuration file  (option  value).   Options
              are case-insensitive.

       BandwidthRate N bytes|KB|MB|GB|TB
              A  token  bucket  limits  the average incoming bandwidth on this
              node to the specified number of bytes per  second.  (Default:  2
              MB)

       BandwidthBurst N bytes|KB|MB|GB|TB
              Limit the maximum token bucket size (also known as the burst) to
              the given number of bytes. (Default: 5 MB)

       MaxAdvertisedBandwidth N bytes|KB|MB|GB|TB
              If set, we will not advertise more than this amount of bandwidth
              for  our  BandwidthRate. Server operators who want to reduce the
              number of clients who ask to build circuits through them  (since
              this  is  proportional  to  advertised  bandwidth rate) can thus
              reduce the CPU demands on their server without impacting network
              performance.

       ControlPort Port
              If  set,  Tor  will  accept  connections  from  the same machine
              (localhost only) on this port, and allow  those  connections  to
              control   the   Tor  process  using  the  Tor  Control  Protocol
              (described in control-spec.txt).  Note: unless you also  specify
              one  of  HashedControlPassword  or CookieAuthentication, setting
              this option will cause Tor to allow any  process  on  the  local
              host to control it.

       HashedControlPassword hashed_password
              Don’t  allow any connections on the control port except when the
              other  process  knows  the  password  whose  one-way   hash   is
              hashed_password.   You  can  compute  the  hash of a password by
              running "tor --hash-password password".

       CookieAuthentication 0|1
              If this option is set to 1, don’t allow any connections  on  the
              control  port  except  when  the  connecting  process  knows the
              contents of a file named "control_auth_cookie", which  Tor  will
              create  in  its  data  directory.   This  authentication methods
              should only be used on systems with  good  filesystem  security.
              (Default: 0)

       DataDirectory DIR
              Store working data in DIR (Default: /var/lib/tor)

       DirFetchPeriod N seconds|minutes|hours|days|weeks
              Every  time  the  specified  period  elapses,  Tor  downloads  a
              directory.  A directory contains a  signed  list  of  all  known
              servers  as well as their current liveness status. A value of "0
              seconds" tells Tor to choose an appropriate default. (Default: 1
              hour for clients, 20 minutes for servers)

       DirServer address:port fingerprint
              Use a nonstandard authoritative directory server at the provided
              address and port, with  the  specified  key  fingerprint.   This
              option  can  be  repeated many times, for multiple authoritative
              directory servers. If no dirserver line is given, Tor  will  use
              the default directory servers: moria1, moria2, and tor26.

       Group GID
              On startup, setgid to this user.

       HttpProxy host[:port]
              Tor  will make all its directory requests through this host:port
              (or host:80 if port is not specified),  rather  than  connecting
              directly to any directory servers.

       HttpProxyAuthenticator username:password
              If  defined,  Tor will use this username:password for Basic Http
              proxy authentication, as in RFC 2617. This is currently the only
              form  of  Http proxy authentication that Tor supports; feel free
              to submit a patch if you want it to support others.

       HttpsProxy host[:port]
              Tor  will  make  all  its  OR  (SSL)  connections  through  this
              host:port  (or  host:443  if  port  is  not specified), via HTTP
              CONNECT rather than connecting directly  to  servers.   You  may
              want  to  set  FascistFirewall  to restrict the set of ports you
              might try to  connect  to,  if  your  Https  proxy  only  allows
              connecting to certain ports.

       HttpsProxyAuthenticator username:password
              If  defined, Tor will use this username:password for Basic Https
              proxy authentication, as in RFC 2617. This is currently the only
              form  of Https proxy authentication that Tor supports; feel free
              to submit a patch if you want it to support others.

       KeepalivePeriod NUM
              To keep firewalls from  expiring  connections,  send  a  padding
              keepalive cell every NUM seconds on open connections that are in
              use. If the connection has no open circuits, it will instead  be
              closed after NUM seconds of idleness. (Default: 5 minutes)

       Log minSeverity[-maxSeverity] stderr|stdout|syslog
              Send  all  messages  between  minSeverity and maxSeverity to the
              standard output stream, the standard error  stream,  or  to  the
              system  log.  (The  "syslog"  value  is only supported on Unix.)
              Recognized severity levels are debug, info,  notice,  warn,  and
              err.   If only one severity level is given, all messages of that
              level or higher will be sent to the listed destination.

       Log minSeverity[-maxSeverity] file FILENAME
              As above, but send log messages to  the  listed  filename.   The
              "Log"  option may appear more than once in a configuration file.
              Messages are sent to all the  logs  that  match  their  severity
              level.

       MaxConn NUM
              Maximum  number  of  simultaneous sockets allowed.  You probably
              don’t need to adjust this. (Default: 1024)

       OutboundBindAddress IP
              Make all outbound connections  originate  from  the  IP  address
              specified.   This  is only useful when you have multiple network
              interfaces, and you want all of Tor’s  outgoing  connections  to
              use a single one.

       PIDFile FILE
              On  startup,  write  our  PID to FILE. On clean shutdown, remove
              FILE.

       RunAsDaemon 0|1
              If 1, Tor forks and daemonizes to the background. (Default: 0)

       SafeLogging 0|1
              If 1, Tor replaces potentially sensitive  strings  in  the  logs
              (e.g.  addresses)  with the string [scrubbed]. This way logs can
              still  be  useful,  but  they  don’t  leave  behind   personally
              identifying  information  about  what  sites  a  user might have
              visited. (Default: 1)

       StatusFetchPeriod N seconds|minutes|hours|days|weeks
              Every time the specified period elapses,  Tor  downloads  signed
              status  information about the current state of known servers.  A
              value of "0 seconds" tells Tor to choose an appropriate default.
              (Default: 30 minutes for clients, 15 minutes for servers)

       User UID
              On startup, setuid to this user.

CLIENT OPTIONS

       The  following  options  are  useful  only  for  clients  (that  is, if
       SOCKSPort is non-zero):

       AllowUnverifiedNodes entry|exit|middle|introduction|rendezvous|...
              Where on our circuits should  we  allow  Tor  servers  that  the
              directory   servers   haven’t   authenticated   as   "verified"?
              (Default: middle,rendezvous)

       ClientOnly 0|1
              If set to 1, Tor will under no circumstances run  as  a  server.
              The  default  is to run as a client unless ORPort is configured.
              (Usually, you don’t need to set this; Tor  is  pretty  smart  at
              figuring  out whether you are reliable and high-bandwidth enough
              to be a useful server.)

              This option will likely be deprecated in  the  future;  see  the
              NoPublish option below. (Default: 0)

       EntryNodes nickname,nickname,...
              A  list  of  preferred  nodes  to  use  for the first hop in the
              circuit, if possible.

       ExitNodes nickname,nickname,...
              A list of preferred nodes  to  use  for  the  last  hop  in  the
              circuit, if possible.

       ExcludeNodes nickname,nickname,...
              A list of nodes to never use when building a circuit.

       StrictExitNodes 0|1
              If  1,  Tor  will  never  use  any nodes besides those listed in
              "exitnodes" for the last hop of a circuit.

       StrictEntryNodes 0|1
              If 1, Tor will never use  any  nodes  besides  those  listed  in
              "entrynodes" for the first hop of a circuit.

       FascistFirewall 0|1
              If  1,  Tor will only create outgoing connections to ORs running
              on ports that your firewall allows (defaults to 80 and 443;  see
              FirewallPorts).   This  will  allow  you  to run Tor as a client
              behind a firewall with restrictive policies, but will not  allow
              you to run as a server behind such a firewall.

       FirewallPorts PORTS
              A  list  of  ports  that your firewall allows you to connect to.
              Only used when FascistFirewall is set. (Default: 80, 443)

       LongLivedPorts PORTS
              A list of ports for services  that  tend  to  have  long-running
              connections  (e.g.  chat  and  interactive shells). Circuits for
              streams that use  these  ports  will  contain  only  high-uptime
              nodes,  to reduce the chance that a node will go down before the
              stream is finished. (Default: 21, 22,  706,  1863,  5050,  5190,
              5222, 5223, 6667, 8300, 8888)

       MapAddress address newaddress
              When a request for address arrives to Tor, it will rewrite it to
              newaddress before processing it. For example, if you always want
              connections  to  www.indymedia.org  to exit via torserver (where
              torserver is  the  nickname  of  the  server),  use  "MapAddress
              www.indymedia.org www.indymedia.org.torserver.exit".

       NewCircuitPeriod NUM
              Every  NUM  seconds  consider  whether  to  build a new circuit.
              (Default: 30 seconds)

       MaxCircuitDirtiness NUM
              Feel free to reuse a circuit that was first  used  at  most  NUM
              seconds  ago, but never attach a new stream to a circuit that is
              too old. (Default: 10 minutes)

       NodeFamily nickname,nickname,...
              The named Tor servers constitute a "family" of  similar  or  co-
              administered  servers,  so never use any two of them in the same
              circuit. Defining a NodeFamily is  only  needed  when  a  server
              doesn’t  list the family itself (with MyFamily). This option can
              be used multiple times.

       RendNodes nickname,nickname,...
              A list of preferred nodes to use for the  rendezvous  point,  if
              possible.

       RendExcludeNodes nickname,nickname,...
              A list of nodes to never use when choosing a rendezvous point.

       SOCKSPort PORT
              Advertise  this  port  to  listen  for  connections  from SOCKS-
              speaking applications.  Set this to 0 if you don’t want to allow
              application connections. (Default: 9050)

       SOCKSBindAddress IP[:PORT]
              Bind  to  this  address  to  listen  for connections from SOCKS-
              speaking applications. (Default: 127.0.0.1) You can also specify
              a  port (e.g. 192.168.0.1:9100). This directive can be specified
              multiple times to bind to multiple addresses/ports.

       SOCKSPolicy policy,policy,...
              Set an entrance policy for this server, to limit who can connect
              to  the  SOCKS  ports.   The policies have the same form as exit
              policies below.

       TrackHostExits host,.domain,...
              For each value in the  comma  separated  list,  Tor  will  track
              recent connections to hosts that match this value and attempt to
              reuse the same exit node for each. If  the  value  is  prepended
              with  a  ’.’, it is treated as matching an entire domain. If one
              of the values is just a ’.’, it  means  match  everything.  This
              option  is  useful  if you frequently connect to sites that will
              expire all your authentication cookies (ie log you out) if  your
              IP  address  changes.  Note  that  this  option  does  have  the
              disadvantage of making it more clear that  a  given  history  is
              associated  with  a  single user. However, most people who would
              wish to observe this will observe it through  cookies  or  other
              protocol-specific means anyhow.

       TrackHostExitsExpire NUM
              Since exit servers go up and down, it is desirable to expire the
              association between host and exit server after  NUM  seconds  of
              inactivity. The default is 1800 seconds (30 minutes).

SERVER OPTIONS

       The  following  options are useful only for servers (that is, if ORPort
       is non-zero):

       Address address
              The IP or fqdn of this  server  (e.g.  moria.mit.edu).  You  can
              leave this unset, and Tor will guess your IP.

       ContactInfo email_address
              Administrative contact information for server.

       ExitPolicy policy,policy,...
              Set  an  exit policy for this server. Each policy is of the form
              "accept|reject ADDR[/MASK][:PORT]".  If /MASK  is  omitted  then
              this policy just applies to the host given.  Instead of giving a
              host or network you can also use  "*"  to  denote  the  universe
              (0.0.0.0/0).   PORT  can be a single port number, an interval of
              ports "FROM_PORT-TO_PORT", or "*".  If  PORT  is  omitted,  that
              means "*".

              For  example, "reject 127.0.0.1:*,reject 192.168.1.0/24:*,accept
              *:*" would reject any traffic destined  for  localhost  and  any
              192.168.1.* address, but accept anything else.

              This directive can be specified multiple times so you don’t have
              to put it all on one line.

              See RFC 3330 for more details about  internal  and  reserved  IP
              address  space.  Policies  are considered first to last, and the
              first match wins. If you want  to  _replace_  the  default  exit
              policy,  end  your  exit  policy  with either a reject *:* or an
              accept *:*. Otherwise, you’re _augmenting_ (prepending  to)  the
              default exit policy. The default exit policy is:
                   reject 0.0.0.0/8
                   reject 169.254.0.0/16
                   reject 127.0.0.0/8
                   reject 192.168.0.0/16
                   reject 10.0.0.0/8
                   reject 172.16.0.0/12
                   reject *:25
                   reject *:119
                   reject *:135-139
                   reject *:445
                   reject *:465
                   reject *:587
                   reject *:1214
                   reject *:4661-4666
                   reject *:6346-6429
                   reject *:6699
                   reject *:6881-6999
                   accept *:*

       MaxOnionsPending NUM
              If  you  have  more  than  this  number of onionskins queued for
              decrypt, reject new ones. (Default: 100)

       MyFamily nickname,nickname,...
              Declare that this Tor server is controlled or administered by  a
              group  or organization identical or similar to that of the other
              named servers.  When two servers both declare that they  are  in
              the  same  ’family’,  Tor  clients will not use them in the same
              circuit.  (Each server only needs to list the other  servers  in
              its  family; it doesn’t need to list itself, but it won’t hurt.)

       Nickname name
              Set the server’s nickname to ’name’.

       NoPublish 0|1
              If you set NoPublish 1, Tor will act as a server if you have  an
              ORPort  defined,  but  it will not publish its descriptor to the
              dirservers. This option is useful if  you’re  testing  out  your
              server,  or if you’re using alternate dirservers (e.g. for other
              Tor networks such as Blossom).  (Default: 0)

       NumCPUs num
              How many processes to use at  once  for  decrypting  onionskins.
              (Default: 1)

       ORPort PORT
              Advertise  this  port to listen for connections from Tor clients
              and servers.

       ORBindAddress IP[:PORT]
              Bind to this IP address  to  listen  for  connections  from  Tor
              clients  and  servers.  If you specify a port, bind to this port
              rather than the one specified in ORPort. (Default: 0.0.0.0)

       RedirectExit pattern target
              Whenever an outgoing connection tries to connect  to  one  of  a
              given set of addresses, connect to target (an address:port pair)
              instead.  The address pattern is given in the same format as for
              an  exit  policy.   The  address  translation applies after exit
              policies are applied.   Multiple  RedirectExit  options  can  be
              used: once any one has matched successfully, no subsequent rules
              are considered.  You can specify that no redirection  is  to  be
              performed  on  a  given  set  of  addresses by using the special
              target string "pass", which prevents subsequent rules from being
              considered.

       ShutdownWaitLength NUM
              When we get a SIGINT and we’re a server, we begin shutting down:
              we close listeners and start refusing new  circuits.  After  NUM
              seconds,   we   exit.  If  we  get  a  second  SIGINT,  we  exit
              immediately.  (Default: 30 seconds)

       DirPostPeriod N seconds|minutes|hours|days|weeks
              Every time the specified period elapses, Tor uploads its  server
              descriptors  to the directory servers.  This information is also
              uploaded whenever it changes.  (Default: 20 minutes)

       AccountingMax N bytes|KB|MB|GB|TB
              Never send more than the specified number of bytes  in  a  given
              accounting  period,  or  receive  more  than  that number in the
              period.  For example, with AccountingMax set to 1 GB,  a  server
              could  send  900  MB and receive 800 MB and continue running. It
              will only hibernate once one of the two reaches 1 GB.  When  the
              number of bytes is exhausted, Tor will hibernate until some time
              in the next accounting period.   To  prevent  all  servers  from
              waking at the same time, Tor will also wait until a random point
              in each period before waking up.  If  you  have  bandwidth  cost
              issues,  enabling  hibernation  is  preferable  to setting a low
              bandwidth, since it provides users with  a  collection  of  fast
              servers  that are up some of the time, which is more useful than
              a set of slow servers that are always "available".

       AccountingStart day|week|month [day] HH:MM
              Specify how long accounting periods last.  If  month  is  given,
              each accounting period runs from the time HH:MM on the dayth day
              of one month to the same day and time of  the  next.   (The  day
              must  be  between  1 and 28.)  If week is given, each accounting
              period runs from the time HH:MM of the dayth day of one week  to
              the same day and time of the next week, with Monday as day 1 and
              Sunday as day 7.  If day is given, each accounting  period  runs
              from  the  time HH:MM each day to the same time on the next day.
              All times are local, and given in 24-hour  time.   (Defaults  to
              "month 1 0:00".)

DIRECTORY SERVER OPTIONS

       The  following  options are useful only for directory servers (that is,
       if DirPort is non-zero):

       AuthoritativeDirectory 0|1
              When this option is set to 1, Tor operates as  an  authoritative
              directory   server.    Instead  of  caching  the  directory,  it
              generates its own list of good servers, signs it, and sends that
              to the clients.  Unless the clients already have you listed as a
              trusted directory, you probably do not want to set this  option.
              Please coordinate with the other admins at tor-ops@freehaven.net
              if you think you should be a directory.

       DirPort PORT
              Advertise the directory service on this port.

       DirBindAddress IP[:PORT]
              Bind the directory service to this address.  If  you  specify  a
              port,  bind  to  this  port  rather  than  the  one specified in
              DirPort. (Default: 0.0.0.0)

       DirPolicy policy,policy,...
              Set an entrance policy for this server, to limit who can connect
              to the directory ports.  The policies have the same form as exit
              policies above.

       RecommendedVersions STRING
              STRING is a command-separated list  of  Tor  versions  currently
              believed to be safe. The list is included in each directory, and
              nodes which pull down the directory learn whether they  need  to
              upgrade.  This option can appear multiple times: the values from
              multiple lines are spliced together.

       DirAllowPrivateAddresses 0|1
              If set to 1, Tor will accept router descriptors  with  arbitrary
              "Address" elements. Otherwise, if the address is not an IP or is
              a private IP, it will reject the router descriptor. Defaults  to
              0.

       RunTesting 0|1
              If  set  to  1,  Tor  tries to build circuits through all of the
              servers it knows about, so it can tell which are  up  and  which
              are   down.   This  option  is  only  useful  for  authoritative
              directories, so you probably don’t want to use it.

HIDDEN SERVICE OPTIONS

       The following options are used to configure a hidden service.

       HiddenServiceDir DIRECTORY
              Store data files for  a  hidden  service  in  DIRECTORY.   Every
              hidden service must have a separate directory.  You may use this
              option multiple times to specify multiple services.

       HiddenServicePort VIRTPORT [TARGET]
              Configure a virtual port VIRTPORT for a hidden service.  You may
              use this option multiple times; each time applies to the service
              using the most recent hiddenservicedir.  By default, this option
              maps  the  virtual  port to the same port on 127.0.0.1.  You may
              override the target port,  address,  or  both  by  specifying  a
              target of addr, port, or addr:port.

       HiddenServiceNodes nickname,nickname,...
              If  possible, use the specified nodes as introduction points for
              the hidden service. If this is left unset, Tor will be smart and
              pick some reasonable ones; most people can leave this unset.

       HiddenServiceExcludeNodes nickname,nickname,...
              Do  not  use  the specified nodes as introduction points for the
              hidden service. In normal use there is no reason to set this.

       RendPostPeriod N seconds|minutes|hours|days|weeks
              Every  time  the  specified  period  elapses,  Tor  uploads  any
              rendezvous  service  descriptors to the directory servers.  This
              information is also uploaded whenever it changes.  (Default:  20
              minutes)

SIGNALS

       Tor catches the following signals:

       SIGTERM
              Tor will catch this, clean up and sync to disk if necessary, and
              exit.

       SIGINT Tor clients behave as with SIGTERM; but Tor servers  will  do  a
              controlled  slow  shutdown,  closing  listeners  and  waiting 30
              seconds before exiting.  (The delay can be configured  with  the
              ShutdownWaitLength config option.)

       SIGHUP The  signal instructs Tor to reload its configuration (including
              closing and reopening logs), fetch a new directory, and kill and
              restart its helper processes if applicable.

       SIGUSR1
              Log  statistics about current connections, past connections, and
              throughput.

       SIGUSR2
              Switch all logs to loglevel debug. You can go back  to  the  old
              loglevels by sending a SIGHUP.

       SIGCHLD
              Tor  receives  this  signal when one of its helper processes has
              exited, so it can clean up.

       SIGPIPE
              Tor catches this signal and ignores it.

       SIGXFSZ
              If this signal exists on your platform, Tor catches and  ignores
              it.

FILES

       /etc/tor/torrc
              The configuration file, which contains "option value" pairs.

       /var/lib/tor/
              The tor process stores keys and other data here.

       /var/log/tor/
              The tor server logs to this directory.

       /var/run/tor/tor.pid
              The PID of the tor (master) process is stored in this file.

SEE ALSO

       privoxy(1), tsocks(1), torify(1)

       http://tor.eff.org/

BUGS

       Plenty, probably. Tor is still in development. Please report them.

AUTHORS

       Roger Dingledine <arma@mit.edu>, Nick Mathewson <nickm@alum.mit.edu>.