Common Uses of AUTAPF



Allow hosts to access a server behind a gateway machine

For reasons such as security, OS compatibility, or just to off-load server resources, you might have a server (daemon) application that runs on a computer other than your Internet-connected machine(s). In these cases AUTAPF can allow clients on the Internet to connect to services provided by machines behind the gateway, that is, machines not directly connected to the Internet. Such functionality is usually provided by gateway routers, but with AUTAPF, can be provided by gateway computers.

Re-direct to non-modifiable custom applications, hard-coded to certain interfaces/ports

Sometimes you have a custom, non-modifiable (or not happily-modifiable) application that listens on a certain local interface and port. In such a case, AUTAPF can be quite useful to allow you to listen to another interface or port. Some example cases are (1) where the application listens to localhost, but now you need to allow clients from other machines to connect, (2) where the application only listens to one local interface, but you want to allow connections from other interfaces, (3) where you want different ports for different interfaces, or (4) where you just want it to listen on one or more additional port numbers, such as if the client wants to connect to a different port number than what's been hard-coded into the server application.

Forward connections from hard-coded localhost (in custom application)

AUTAPF can be useful or even save the day when you have a custom application that makes connections to localhost (the local machine) and you later want to make it connect somewhere else. Also, it's useful to make a custom application connect to a port on localhost, such as a higher, less-common, port number and then have AUTAPF be part of your system to later be able to quickly change the destination host and/or port without the need to modify the custom application. Such practice is particularly useful when the destination host is based on an third-party service that might later be changed, such as POP3, SMTP, etc..

Add the ability to log connections of a server/client pair

If you have a client/server pair, particularly a custom TCP or UDP based solution that doesn't currently provide the ability to log connections, AUTAPF could perhaps help. Though AUTAPF doesn't provide protocol-specific information, it could still let you log which hosts connected and at what times. This might help with post-event security analysis or to troubleshoot client/server connection problems.

Free a port used by non-port-configurable but interface-configurable local service/daemon

In this case, AUTAPF could allow you to change the port used by such a service. This is useful when the service is necessary, but where you want something else on that port number instead. There are a few cases, but two are as follows. (1) In the case that the service is accessed from other computers, you could set the service to listen on localhost and then have AUTAPF listen on the actual network interface and forward connections to localhost. (2) In the case that the service is accessed at its localhost address as well as from abroad, you could perhaps, granted you have Windows 2000 or later, add another IP address to the network adapter through the network adapter's TCP/IP properties dialog (in Advanced->IP Settings->IP addresses->Add - granted it's not set to DHCP) and then configure the service to listen on the new IP address and configure AUTAPF to listen to the original IP address on a different port than the service listens on and have it forward to the new IP address just created for the service.

Block/allow certain IP addresses from connection to your daemon

AUTAPF could allow you to filter clients by IP address. To do this, simply set your daemon to listen on localhost and then have AUTAPF listen on the main network interface(s) and forward the connections to localhost. AUTAPF allows you to filter based on IP in the configuration for each port forward. Each forward has its own IP filters. Furthermore, AUTAPF can take dynamic filters in from a text-file that can be updated in real-time. Such a text-file could be modified as needed by an external program or script.

Assess client/server data throughput, current data-rate, and number of connections

AUTAPF shows the current data-rate for each port forward and also totals the data-bytes from each direction for all connections on the forward so far. Furthermore, the current and total number of connections since a forward started is shown. This information can be useful for performance analysis and general bandwidth summation for a particular server application.

Maintain access to server on a dynamic or unreliable network interface

If your server/daemon software stops after the dynamic or unreliable network/Internet interface goes down and comes back up, AUTAPF may be able to help. AUTAPF can track one or more dynamic network interface and continue to listen on the interface even after interface downage or IP address re-lease (DHCP renew). In this case, simply have the server/daemon software listen on localhost and have AUTAPF maintain its port on the inconsistent network interface, and set AUTAPF to forward the connections to localhost.

Script your port forwards into action

When it comes to automated IT systems, scripts and component-interaction are commonplace. Should you need scripted or application-controlled creation or modification of UDP or TCP port forwards, AUTAPF can be your friend. AUTAPF stores its configuration (and forwards) in a text-based file named after the executable. The .NAS file located with the executable can be modified or created by an external program. To utilise this feature, simply create a forward in AUTAPF, close it and open the configuration file to see the format, then code your script or external program to make or modify the AUTAPF configuration file as needed. It would simply stop AUTAPF, make/modify the file, and then start AUTAPF. If AUTAPF is installed as a Windows service, simply execute net stop AUTAPF and net start AUTAPF via your script. Additional notes for the coder: The file is in wide-char format and should be saved as such. Be sure not to miss any invisible tabs on the forward lines. All lines can be in any order. Everything is case-sensitive.