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https://github.com/troglobit/redir

A TCP port redirector for UNIX
https://github.com/troglobit/redir

inetd tcp-port-redirector

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A TCP port redirector for UNIX

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A TCP port redirector for UNIX

==============================

[![GitHub Status][]][GitHub] [![Coverity Status]][Coverity Scan]



This is a TCP port redirector for UNIX.  It can be run under inetd or as

a standalone daemon (in which case it handles multiple connections).  It

is 8-bit clean, not limited to line mode, yet small and lightweight.  If

you want access control, run it under xinetd or inetd with TCP wrappers.



`redir` listens for TCP connections on a given `SRC:PORT`.  When clients

connect to `redir` it initiates a connection to the server on `DST:PORT`

to pass data between them.  The `SRC` and `DST` are from the perspective

of `redir`.



```

                      -------> SRC:PORT -----> DST:PORT



Request:       CLIENT -------> redir --------> SERVER



Response:      CLIENT <------- redir <-------- SERVER

                                     --bind=addr

```



**Note:** the `--bind=ADDR` argument is to limit `redir` on the server

side reply, in case the box `redir` runs on have multiple addresses or

interfaces on the server side.



> `redir` finds most of its applications in traversing firewalls, but,

> of course, there are other use-cases.  For a UDP port redirector, see

> [uredir](https://github.com/troglobit/uredir/)



Usage

-----



Consult the man page for details.



    Usage: redir [-hinspv] [-b IP]  [-f TYPE] [-I NAME] [-l LEVEL] [-t SEC]

                           [-x STR] [-m BPS] [-o FLAG] [-w MSEC] [-z BYTES]

                           [SRC]:PORT [DST]:PORT

    Options:

      -b, --bind=IP            Listen only to IP on the server-side connection,

                               how DST connects to redir. Not applicable with -p

      -f, --ftp=TYPE           Redirect FTP connections.  Where type is

                               one of: 'port', 'pasv', or 'both'

      -h, --help               Show this help text

      -i, --inetd              Run from inetd, SRC:PORT comes from stdin

                               Usage: redir [OPTIONS] [DST]:PORT

      -I, --ident=NAME         Identity, tag syslog messages with NAME

                               Also used as service name for TCP wrappers

      -l, --loglevel=LEVEL     Set log level: none, err, notice*, info, debug

      -n, --foreground         Run in foreground, do not detach from terminal

      -p, --transproxy         Run in Linux's transparent proxy mode

      -s, --syslog             Log messages to syslog

      -t, --timeout=SEC        Set timeout to SEC seconds, default off (0)

      -v, --version            Show program version

      -x, --connect=STR        CONNECT string passed to proxy server

    

    Traffic Shaping:

      -m, --max-bandwidth=BPS  Limit the bandwidth to BPS bits/second

      -o, --wait-in-out=FLAG   Wait for in(1), out(2), or in&out(3)

      -w, --random-wait=MSEC   Wait MSEC milliseconds before each packet

      -z, --bufsize=BYTES      Size of the traffic shaping buffer

    

    SRC and DST are optional, redir will revert to use 0.0.0.0 (ANY)



### Old Syntax



Command line options changed in v3.0.  A limited subset of the old

syntax is available with the `--enable-compat` configure option.

This implicitly also enables `-n` by default.



The following subset of the old syntax are available:



	  --lport=PORT             Local port (when not running from inetd)

	  --laddr=ADDRESS          Local address (when not running from inetd)

	  --cport=PORT             Remote port to redirect traffic to

	  --caddr=ADDRESS          Remote address to redirect traffic to



Examples

--------



To redirect port 80 to a webserver listening on loopback port 8080,

remember to use `sudo` when using priviliged ports:



    sudo redir :80 127.0.0.1:8080



This starts `redir` as a standard UNIX daemon in the background, with

all log messages sent to the syslog.  Use `-n` to foreground and see log

messages on `stderr`.



To run `redir` from a process monitor like [Finit][] or systemd, tell it

to not background itself and to only use the syslog for log messages:



    redir -n -s :80 127.0.0.1:8080



An `/etc/inetd.conf` line of the same looks very similar:



    http  stream  tcp  nowait  root  /usr/sbin/tcpd /usr/bin/redir -n -s -i 127.0.0.1:8080



When running multiple redir instances it can be useful to change how

they identify themselves:



    redir -I nntp www:119 netgate:119

    redir -I pop3 ftp:110 netgate:110



This starts an NNTP and a POP3 port redirector, named accordingly.

Previously therere was a `redir-wrapper` script included in the

distribution, but that is no longer maintained.



Building

--------



Redir comes with a  GNU configure script which you can  use to adapt the

build  to your  needs.  If  you would  like to  remove support  for some

extended options (for  the sake of speed, code size,  whatever), try the

following options to configure:



    --enable-compat    Enable limited v2.x command line syntax

    --disable-shaper   Disable traffic shaping code

    --disable-ftp      Disable FTP redirection support



The GNU Configure & Build system use `/usr/local` as the default install

prefix.  For most use-cases this is fine, but if you want to change this

to `/usr` use the `--prefix=/usr` configure option:



    ./configure --prefix=/usr

    make -j5

    sudo make install-strip



Building from GIT sources require you have `automake` and `autoconf`

installed.  Use `./autogen.sh` to create the configure script.



Origin & References

-------------------



Redir was originally created by Nigel Metheringham and [Sam Creasey][].

It is now maintained at [GitHub][1] by [Joachim Wiberg][].  Use GitHub

to file bug reports, clone, or send pull requests for bug fixes and

extensions.



Redir is distributed under the terms of the GNU Public Licence, version

2 or later, distributed with this source archive in the file COPYING.



[Sam Creasey]:     http://sammy.net/~sammy/hacks/

[Joachim Wiberg]:  http://troglobit.com

[1]:               https://github.com/troglobit/redir

[Finit]:           https://github.com/troglobit/finit

[GitHub]:          https://github.com/troglobit/redir/actions/workflows/build.yml/

[GitHub Status]:   https://github.com/troglobit/redir/actions/workflows/build.yml/badge.svg

[Coverity Scan]:   https://scan.coverity.com/projects/8740

[Coverity Status]: https://scan.coverity.com/projects/8740/badge.svg