.TH TOR 1 "November 2004" "TOR" .SH NAME tor \- The second-generation onion router .SH SYNOPSIS .B tor [\fIOPTION value\fR]... .SH DESCRIPTION .I 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. .PP Basically \fItor\fR 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. .SH OPTIONS \fB-h, -help\fP Display a short help message and exit. .TP \fB-f \fR\fIFILE\fP FILE contains further "option value" pairs. (Default: @CONFDIR@/torrc) .TP Other options can be specified either on the command-line (\fI--option value\fR), or in the configuration file (\fIoption value\fR). Options are case-insensitive. .TP \fBLog \fR\fIminSeverity\fR[-\fImaxSeverity\fR] \fBstderr\fR|\fBstdout\fR|\fBsyslog\fR\fP Send all messages between \fIminSeverity\fR and \fImaxSeverity\fR 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. .TP \fBLog \fR\fIminSeverity\fR-\fImaxSeverity\fR \fBfile\fR \fIFILENAME\fP 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. .TP \fBBandwidthRateBytes \fR\fINUM\fP A token bucket limits the average incoming bandwidth on this node to NUM bytes per second. (Default: 800000) .TP \fBBandwidthBurstBytes \fR\fINUM\fP Limit the maximum token bucket size (also known as the burst) to NUM bytes. (Default: 50000000) .TP \fBDirServer \fR\fIaddress:port fingerprint\fP 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 \fBdirserver\fP line is given, Tor will use the default directory servers: moria1, moria2, and tor26. .TP \fBGroup \fR\fIGID\fP On startup, setgid to this user. .TP \fBHttpProxy\fR \fIhost\fR[:\fIport\fR]\fP If set, Tor will make all its directory requests through this host:port, rather than connecting directly to any directory servers. .TP \fBKeepalivePeriod \fR\fINUM\fP To keep firewalls from expiring connections, send a padding keepalive cell on open connections every NUM seconds. (Default: 300) .TP \fBMaxConn \fR\fINUM\fP Maximum number of simultaneous sockets allowed. You probably don't need to adjust this. (Default: 1024) .TP \fBOutboundBindAddress \fR\fIIP\fP 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. .TP \fBPIDFile \fR\fIFILE\fP On startup, write our PID to FILE. On clean shutdown, remove FILE. .TP \fBRunAsDaemon \fR\fB0\fR|\fB1\fR\fP If 1, Tor forks and daemonizes to the background. (Default: 0) .TP \fBUser \fR\fIUID\fP On startup, setuid to this user. .SH CLIENT OPTIONS .PP The following options are useful only for clients (that is, if \fBSOCKSPort\fP is non-zero): .TP \fBAllowUnverifiedNodes\fR \fBentry\fR|\fBexit\fR|\fBmiddle\fR|\fBintroduction\fR|\fBrendezvous\fR|...\fP Where on our circuits should we allow Tor servers that the directory servers haven't authenticated as "verified"? (Default: middle,rendezvous.) .TP \fBDirFetchPostPeriod \fR\fIseconds\fP Every N seconds, Tor downloads a fresh directory, and re-uploads information about hidden services to the directory servers. If running as a server, Tor also re-uploads information about itself to the directory servers. (Tor also uploads this information whenever it changes.) (Default: 600.) .TP \fBClientOnly \fR\fB0\fR|\fB1\fR\fP If set to 1, Tor will under no circumstances run as a server. (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 good server.) .TP \fBEntryNodes \fR\fInickname,nickname,...\fP A list of preferred nodes to use for the first hop in the circuit, if possible. .TP \fBExitNodes \fR\fInickname,nickname,...\fP A list of preferred nodes to use for the last hop in the circuit, if possible. .TP \fBExcludeNodes \fR\fInickname,nickname,...\fP A list of nodes to never use when building a circuit. .TP \fBStrictExitNodes \fR\fB0\fR|\fB1\fR\fP If 1, Tor will never use any nodes besides those listed in "exitnodes" for the last hop of a circuit. .TP \fBStrictEntryNodes \fR\fB0\fR|\fB1\fR\fP If 1, Tor will never use any nodes besides those listed in "entrynodes" for the first hop of a circuit. .TP \fBFascistFirewall \fR\fB0\fR|\fB1\fR\fP If 1, Tor will only create outgoing connections to ORs running on ports that your firewall allows (defaults to 80 and 443; see \fBFirewallPorts\fR). 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. .TP \fBFirewallPorts \fR\fIPORTS\fP A list of ports that your firewall allows you to connect to. Only used when \fBFascistFirewall\fR is set. (Default: 80, 443.) .TP \fB \fBNewCircuitPeriod \fR\fINUM\fP Every NUM seconds consider whether to build a new circuit. (Default: 60) .TP \fBNodeFamily \fR\fInickname,nickname,...\fP 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. .TP .\" \fBPathlenCoinWeight \fR\fI0.0-1.0\fP .\" Paths are 3 hops plus a geometric distribution centered around this coinweight. Must be >=0.0 and <1.0. (Default: 0.3) NOT USED CURRENTLY .\" .TP \fBRendNodes \fR\fInickname,nickname,...\fP A list of preferred nodes to use for the rendezvous point, if possible. .TP \fBRendExcludeNodes \fR\fInickname,nickname,...\fP A list of nodes to never use when choosing a rendezvous point. .TP \fBSOCKSPort \fR\fIPORT\fP Bind to 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) .TP \fBSOCKSBindAddress \fR\fIIP\fP 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. .TP \fBSOCKSPolicy \fR\fIpolicy,policy,...\fP 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. .SH SERVER OPTIONS .PP The following options are useful only for servers (that is, if \fBORPort\fP is non-zero): .TP \fBAddress \fR\fIaddress\fP The IP or fqdn of this server (e.g. moria.mit.edu). .TP \fBDataDirectory \fR\fIDIR\fP Store working data in DIR (Default: @LOCALSTATEDIR@/lib/tor) .TP \fBExitPolicy \fR\fIpolicy,policy,...\fP Set an exit policy for this server. Each policy is of the form "\fBreject\fP \fIADDR\fP\fB/\fP\fIMASK\fP\fB:\fP\fIPORT\fP". If \fB/\fP\fIMASK\fP is omitted then this policy just applies to the host given. Instead of giving a host or network you can also use "\fB*\fP" to denote the universe (0.0.0.0/0). \fIPORT\fP can either be a single port number or an interval of ports: "\fIFROM_PORT\fP\fB-\fP\fITO_PORT\fP". 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. The default exit policy is: .PD 0 .RS 12 .IP "reject 0.0.0.0/8" 0 .IP "reject 169.254.0.0/16" 4 .IP "reject 127.0.0.0/8" .IP "reject 192.168.0.0/16" .IP "reject 10.0.0.0/8" .IP "reject 172.16.0.0/12" .IP "accept *:20-22" .IP "accept *:53" .IP "accept *:79-81" .IP "accept *:110" .IP "accept *:143" .IP "accept *:443" .IP "accept *:873" .IP "accept *:993" .IP "accept *:995" 4 .IP "reject *:4661-4662" .IP "reject *:1214" .IP "reject *:6346" .IP "accept *:1024-65535" .IP "reject *:*" .RE .PD .TP \fBMaxOnionsPending \fR\fINUM\fP If you have more than this number of onionskins queued for decrypt, reject new ones. (Default: 100) .TP \fBMyFamily \fR\fInickname,nickname,...\fP 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. .TP \fBNickname \fR\fIname\fP Set the server's nickname to 'name'. .TP \fBNumCPUs \fR\fInum\fP How many processes to use at once for decrypting onionskins. (Default: 1) .TP \fBORPort \fR\fIPORT\fP Bind to this port to listen for connections from Tor clients and servers. .TP \fBORBindAddress \fR\fIIP\fP Bind to this address to listen for connections from Tor clients and servers. (Default: 0.0.0.0) .TP \fBRedirectExit \fR\fIpattern target\fP Whenever an outgoing connection tries to connect to one of a given set of addresses, connect to \fItarget\fP (an \fIaddress:port\fP 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 \fBRedirectExit\fP 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. .TP \fBAccountingMaxKB \fR\fInum\fP Never send or receive more than \fInum\fP kilobytes in a given accounting period (currently, only months are supported). When the number of kilobytes is exhausted, Tor will hibernate until some time in the next accounting period. If you have bandwidth cost issues, using this option 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". .TP \fBMonthlyAccountingStart \fR\fIday\fP Always start the accounting period on the provided day of the month, which must be between 1 and 28. (Defaults to 1.) .SH DIRECTORY SERVER OPTIONS .PP The following options are useful only for directory servers (that is, if \fBDirPort\fP is non-zero): .TP \fBAuthoritativeDirectory \fR\fB0\fR|\fB1\fR\fP 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. .TP \fBContactInfo \fR\fIemail address\fP Administrative contact information for server. .TP \fBDirPort \fR\fIPORT\fP Bind the directory service to this port. .TP \fBDirBindAddress \fR\fIIP\fP Bind the directory service to this address. (Default: 0.0.0.0) .TP \fBDirPolicy \fR\fIpolicy,policy,...\fP 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. .TP \fBRecommendedVersions \fR\fISTRING\fP 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. .TP \fBRunTesting \fR\fB0\fR|\fB1\fR\fP 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. .SH HIDDEN SERVICE OPTIONS .PP The following options are used to configure a hidden service. .TP \fBHiddenServiceDir \fR\fIDIRECTORY\fP 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. .TP \fBHiddenServicePort \fR\fIVIRTPORT \fR[\fITARGET\fR]\fP 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. .TP \fBHiddenServiceNodes \fR\fInickname,nickname,...\fP If possible, use the specified nodes as introduction points for the hidden service. .TP \fBHiddenServiceExcludeNodes \fR\fInickname,nickname,...\fP Do not use the specified nodes as introduction points for the hidden service. .\" UNDOCUMENTED .\" ignoreversion .SH FILES .TP .I @CONFDIR@/torrc The configuration file, which contains "option value" pairs. .TP .I @CONFDIR@/dirservers A list of directory servers, to bootstrap into the network. .TP .I @LOCALSTATEDIR@/lib/tor/ The tor process stores keys and other data here. .SH SEE ALSO .BR privoxy (1), .BR tsocks (1), .BR torify (1) .BR http://freehaven.net/tor/ .SH BUGS Plenty, probably. It's still in alpha. Please report them. .SH AUTHORS Roger Dingledine , Nick Mathewson .