access a vfp exe without port forwarding

[MarkLeT]

My apologies if this has been answered elsewhere.

I have created a vfp system tray program (exe1) that will collect public IP, local IP, and random port information for the computer on which it resides and transmit it to a secure server. It will then "listen" on that port for incoming connection (like Logmein). I wish to create another program that will pick up that information and communicate with exe1 to exchange information. Basically, I wish to create a web server without having to configure port forwarding. I figure if Logmein and Teamviewer can do it, it must not be too difficult to set up, but I can find no information anywhere on the web on how to do it. Please help!

 

[Olaf Doschke]

The "secret" of tools like Teamviewer is, they work on port 80 for http, port 443 for https (ssl). Ports are typically closed and would need to be opened in firewalls.

https://www.teamviewer.com/en/help/334-Which-ports-are-used-by-TeamViewer

Bye, Olaf.

 

[DSummZZZ]

I figure if Logmein and Teamviewer can do it, it must not be too difficult to set up...

If it was that easy, there would be a lot more people doing it and they would be charging a bunch of money for it.
Add to that, there is some major authentication going on behind the scenes.

I'm sure something could be set up to relay information or connections. But in order to avoid port forwarding, you'll have to leave that port open - as in, not behind any firewall. Which isn't really a good idea.
But, when you open a socket to listen, you will have to know the port number. So you won't be using a random port number anyway.


-Dave Summers-

Even more Fox stuff at:

http://www.dave-summers.net/foxprolinks.htm

 

[MarkLeT]

No matter the port number, these programs somehow go around firewalls. But even if the port is open and not forwarded, how do you navigate to the local ip address within the network?

 

[Olaf Doschke]

You don't have to go around firewalls, if using port 80.

 

[DSummZZZ]

They don't really go around firewalls. When they're installed, they 'Allow' themselves through the port(s) they use in the firewall. That is something there is no getting around.
To navigate to an open port using http, you add the port to the end of the IP. As in

http://xxx.xxx.xxx.xxx:123.

Telnet uses OPEN xxx.xxx.xxx.xxx 123. Using straight IP connections, you specify the IP and port in whatever socket control you use:

WITH THISFORM.oWinsock.oSock
   .protocol = sckTCPProtocol
   *... Remote Host name
   .remoteHost = Thisform.cTCPHost
   *... Remote Port
   .remotePort = Thisform.cTCPPort
   *...   '0' to use any available Local Port.  If you've opened a secific
   *...   port before, you'll have to wait for the ip stack to release it
   *...   before it can be reused.
   .localPort = 0
   .OBJECT.CONNECT()
ENDWITH

-Dave Summers-

Even more Fox stuff at:

http://www.dave-summers.net/foxprolinks.htm