NetCallback is a Java application that enables the export of TCP and UDP ports to external hosts outside a firewall.
NetCallback consists of two servers: the public server and the private server. The public server runs on a host outside the firewall and is responsible for receiving port forwarding connection requests. The private server runs on a host behind the firewall and is responsible for connecting the protected TCP and/or UDP service to the public server clients by contacting the public server.
The connection between the public and private servers can be encrypted using SSL if desired. However, it's important to note that firewalls exist to protect internal services from outside access, so creating a hole in one should be done with care. The program is distributed in the hope that it will be useful, but it comes without warranty.
Using the NetCallback service requires the execution of two network daemons. The first daemon is the PrivateServer, which should be run on a host behind the firewall. The second daemon is the PublicServer, which should be run on a host outside the firewall. The PublicServer is invoked with three port numbers, one for receiving connection requests, another for clients to connect to the TCP port forwarding endpoint, and a third for UDP.
The PrivateServer is invoked with both the host name and service port number of PublicServer, as well as the address and port number of a TCP and/or UDP internal service that needs to be exported. Before using this software, users should check their network use policy for possible violations and use at their own risk.
Version 1.3.1: N/A