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TSOCKS(8) | System Manager's Manual | TSOCKS(8) |
NAME¶
tsocks - Library for intercepting outgoing network connections and redirecting them through a SOCKS server.SYNOPSIS¶
Set LD_PRELOAD to load the library then use applications as normalDESCRIPTION¶
tsocks is a library to allow transparent SOCKS proxying. It wraps the normal connect() function. When a connection is attempted, it consults the configuration file (which is defined at configure time but defaults to ~/.tsocks.conf and if that file cannot be accessed, to /etc/tsocks.conf) and determines if the IP address specified is local. If it is not, the library redirects the connection to a SOCKS server specified in the configuration file. It then negotiates that connection with the SOCKS server and passes the connection back to the calling program.ARGUMENTS¶
Most arguments to tsocks are provided in the configuration file (the location of which is defined at configure time by the --with-conf=<file> argument but defaults to /etc/tsocks.conf). The structure of this file is documented in tsocks.conf(8)- TSOCKS_CONF_FILE
- This environment variable overrides the default location of
the tsocks configuration file. This variable is not honored if the program
tsocks is embedded in is setuid. In addition this environment variable can
be compiled out of tsocks with the --disable-envconf argument to configure
at build time
- TSOCKS_DEBUG
- This environment variable sets the level of debug output
that should be generated by tsocks (debug output is generated in the form
of output to standard error). If this variable is not present by default
the logging level is set to 0 which indicates that only error messages
should be output. Setting it to higher values will cause tsocks to
generate more messages describing what it is doing. If set to -1 tsocks
will output absolutely no error or debugging messages. This is only needed
if tsocks output interferes with a program it is embedded in. Message
output can be permanently compiled out of tsocks by specifying the
--disable-debug option to configure at build time
- TSOCKS_DEBUG_FILE
- This option can be used to redirect the tsocks output
(which would normally be sent to standard error) to a file. This variable
is not honored if the program tsocks is embedded in is setuid. For
programs where tsocks output interferes with normal operation this option
is generally better than disabling messages (with TSOCKS_DEBUG = -1)
- TSOCKS_USERNAME
- This environment variable can be used to specify the
username to be used when version 5 SOCKS servers request username/password
authentication. This overrides the default username that can be specified
in the configuration file using 'default_user', see tsocks.conf(8) for
more information. This variable is ignored for version 4 SOCKS servers.
- TSOCKS_PASSWORD
- This environment variable can be used to specify the
password to be used when version 5 SOCKS servers request username/password
authentication. This overrides the default password that can be specified
in the configuration file using 'default_pass', see tsocks.conf(8) for
more information. This variable is ignored for version 4 SOCKS servers.
DNS ISSUES¶
tsocks will normally not be able to send DNS queries through a SOCKS server since SOCKS V4 works on TCP and DNS normally uses UDP. Version 1.5 and up do however provide a method to force DNS lookups to use TCP, which then makes them proxyable. This option can only enabled at compile time, please consult the INSTALL file for more information.ERRORS¶
tsocks will generate error messages and print them to stderr when there are problems with the configuration file or the SOCKS negotiation with the server if the TSOCKS_DEBUG environment variable is not set to -1 or and --disable-debug was not specified at compile time. This output may cause some problems with programs that redirect standard error.CAVEATS¶
tsocks will not in the above configuration be able to provide SOCKS proxying to setuid applications or applications that are not run from a shell. You can force all applications to LD_PRELOAD the library by placing the path to libtsocks in /etc/ld.so.preload. Please make sure you correctly enter the full path to the library in this file if you do this. If you get it wrong, you will be UNABLE TO DO ANYTHING with the machine and will have to boot it with a rescue disk and remove the file (or try the saveme program, see the INSTALL file for more info). THIS IS A ***WARNING***, please be careful. Also be sure the library is in the root filesystem as all hell will break loose if the directory it is in is not available at boot time.BUGS¶
tsocks can only proxy outgoing TCP connectionsFILES¶
/etc/tsocks.conf - default tsocks configuration fileSEE ALSO¶
tsocks.conf(5) tsocks(1)AUTHOR¶
Shaun Clowes (delius@progsoc.uts.edu.au)COPYRIGHT¶
Copyright 2000 Shaun ClowesShaun Clowes |