Accordata Port-Proxy V0.95

Port-Proxy is Perl script to forward ports from the local system to another system.
When using https-tunneling you are able to go through an firewall.

Features:

• Port forwarding an the same system
• Port forwarding to an remote system
• Testet with Linux and Windows
• Forward over https-tunnel to port 443
• Forward over https-tunnel to any port

Install:

• Install Perl
• Download the zip
• Unzip to an any directory
• Edit configuration file
• Start programm

Configuration

All the configuration is done in the file port-proxy.conf, which is readed from the current directory when starting port-proxy.pl.
There are the following parameters which can apear multiple times:

forward=local addr,destination addr,[proxy 1],[proxy 2]

local addr	Define where port-proxy listen for connections. It can be either a port or an address with port (eg. 127.0.0.1:8080; localhost:8080) Without an address your system listens on all interfaces, also an dialup line.
destination addr	Defines the destination as addr:port (eg. 192.168.0.1:80 or remotehost.com:80) Please note: If you use an proxy, this address is from the view of the proxy. If you use localhost or 127.0.0.1 it addresses the proxy host. If you enter the special address [PROXY], port-proxy.pl behave like an https proxy an reads the destination from the connecting client.
proxy 1	Defines an https proxy to use.
proxy 2	Defines an 2nd https proxy to use. This is usally port-proxy.pl listening an port 443

allow_proxy_to=addr
Defines which destinations are allowed if you use [PROXY] as destination.
Addr is executed with perl regex and my be something like this:
allow_proxy_to=localhost:23 # allow telnet
allow_proxy_to=192.168..*:80 # http to all 192.168.x.x

Example 1: Port forwarding
Task: Allow access to a service on a know host
[client] --- [proxy] --- [remote]
Your client has no access to [remote], but has access to [proxy]
To fetch mail from [remote], you may configure on [proxy]:
forward=110,remote.com:110
Your client connects to [proxy] an port 110 an fetches mail from remote.com.

Example 2: Port forwarding with https tunnel
Task: Your client want to telnet to a know host, but is behind an firewall with only access to an https proxy.
Configuration on Client (not working): forward=localhost:9023,remote.com:23,https-proxy:8080
Since most proxys allow only connection to port 443 you don't has access to remote.com:23.
To get it work, you need to setup telnet on port 443 at remote.com:

• Insert in inetd.conf of remote.com: 443 stream tcp nowait root /usr/sbin/tcpd in.telnetd
• Use configuration: forward=localhost:9023,remote.com:443,https-proxy:8080
• On your client use: telnet localhost 9023

Example 3: Port forwarding with https tunnel and an special proxy to access individual remote addesses
[client] --- [https-proxy] --- [remote host proxy:443] -- [remote service]
To cover the problems noted above, port-proxy.pl can behave like an proxy listening an port 443 and forward to your needed service.
You need to run port-proxy.pl on [client] and [remote]

port-proxy.conf on your client (telnet example):
forward=localhost:9023,localhost:23,https-proxy:8080,remote.com:443
(Note: 'localhost:23' is from the view of remote.com. Therefore it addresses telnet on remote.com)

port-proxy.conf on remote.com:
forward=443,[PROXY] # Listen on port 443 and behave like an https proxy
allow_proxy_to=localhost:23 # telnet

Connection flow:

• On client: telnet localhost:9023
• port-proxy.pl connects to https-proxy:8080
• https-proxy connects to remote.com:443
• port-proxy.pl an remote.com connects localhost:23 (telnet)

Running port-proxy.pl

perl port-proxy.pl [-d] [-D] [-c conffile]

-d	Enable debug output
-D	Become a background process (detach don't work on windows)
-c conffile	Specify an config file

Example:
perl port-proxy -D -c /etc/port-proxy.conf

License

• You are allowed to use and distribut without changes
• If you distribute modified version, you must not remove the copyright or author information.
  You should document the changes and may add your copyright for that parts.
• If you use parts in your software, you should honor our work somewhere in your documentation.