This application opens a port and start listen on it and then forward the traffic to a remote proxy. This has the option to set the local source port to the outbound connection. This could be helpful in firewalls rules that allow traffic from a range of remote ports, the remote ports for them is our source port here.
The portForwardReuse.php file is an attempt to avoid droping the two sockets opened when a close connection exist from one of them. Two sockets are opened one for listening and the other to connect to the remote side. If one socket is dropped then it will try to start other one while reusing the socket that is still connected, but this is not actually working, the two dropped at the end.
The working script is the portForward.php file, this case works when one of the socket closes, then both sockets are force to close and terminate the connection and then the application wait for a new connection. This approach is better than the other one.
The config_example.php file should be rename to config.php, this file return an array that will create the config variables used in the application.
<?php
return [
'localAddress' => '127.0.0.1',
'remoteAddress' => '127.0.0.1',
'lclPort' => 8081,
'dstPort' => 8083,
'socketSendSrcPorts' => [] // [5001, 50002, 5547]
];The localAddress is the ip or interface from which the application start to listen.
The remoteAddress is the the proxy where the traffic is routed.
The lclPort is the listening port, the application waits for new connections.
The dstPort is the remote port to connect to, to where the traffic is routed.
The socketSendSrcPorts are the sources ports to choose from for the outbound connection to remoteAddress and dstPort. Realize that if you set 3 source ports, you have only 3 inbound connections accepted. If the socketSendSrcPorts is an empty array then the S.O. will choose a random source port as usual.
To run the script, just open a commandline in the directory of the files, and type
C:\portFoward2Proxy>php portForward.php