nportredird - TCP/IP Networks Port Redirector Ayman Akt ayman@pobox.com Version 0.6 18/03/2001
Table of Contents
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Copyright
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Introduction
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Installation
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Running
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Contribution
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Bugs
1�1.�. C�Co�op�py�yr�ri�ig�gh�ht�t
This software is Copyright (c) 1999-2001 Ayman Akt. nportredird is released under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
Please consult the file COPYING for the exact terms.
2�2.�. I�In�nt�tr�ro�od�du�uc�ct�ti�io�on�n
Nportredird is a UNIX server program that can redirect (forward) TCP/IP connections between servers and clients. It acts as a "middle man" and therefore can enforce certain policies. Currently supported policies:
+�o Access restrictions based on IP addresses.
+�o Limit on the number of concurrent connections.
This is very popular concept and extremely useful in situations where certain protected services need to be exposed to the outside--securely.
Nportredird can handle multible, concurrent connections to one, or more remote ends making it ideal as a central redirection facility.
Nportredird offers many variations on the concept of redirection which can be helpful for people with rather exotic demands. For example you can redirect an incoming connection to /dev/null, or fork multible redirections off the same port number based on IP addresses (also known within the program as intra-redirection).
The implementation is multi-threaded and scales very well. Its memory footprint is quite light.
The software lacks quite a few features, which I hope to implement later:
+�o UDP connections are not supported
+�o ftp traffic cannot be redirected
3�3.�. I�In�ns�st�ta�al�ll�la�at�ti�io�on�n
Please read the INSTALL file for detailed intructions. The installation procedure follows the standard UNIX convention, namely;
_�._�/_�c_�o_�n_�f_�i_�g_�u_�r_�e_�; _�m_�a_�k_�e_�; _�m_�a_�k_�e _�i_�n_�s_�t_�a_�l_�l
A sample configuration file is provided. It's copied to /etc/nportredird by default.
4�4.�. R�Ru�un�nn�ni�in�ng�g
The defaults insure command-line parameters-free invocation. The server will run in daemon mode by default, i.e. it will detach itself from the controlling terminal and log with your system's syslog facility. Please run the software with the '-h' switch for more details.
The programs is completely configuration file-driven; therefore you have to write one that reflects your needs. The configuration file is well structured and quite easy to put together. A sample file is provided.
A standard UNIX man page is also provided and offers some hints and information on the various invocation modes and features. The man page is currently the most uptodate and authoritative documentation available.
5�5.�. C�Co�on�nt�tr�ri�ib�bu�ut�ti�io�on�n
I've set up a mailing list and discussion group at http://www.egroups.com/group/nportredird. You can join through the web interface, or send e-mail to nportredird-subscribe@egroups.com
6�6.�. B�Bu�ug�gs�s
The program has been in use in production systems for quite some time and seems to hang together very well. But, I have been toying with it lately and added some "features", and those features cut right through the thing, therefore I'm not sure how well-behaved they are. My initial tests look OK.
Please read the BUGS file for any known issues.
You can send your bug reports to the mailing list at http://www.egroups.com/group/nportredird