File Tunnel

Tunnel TCP connections through a file.

Download

Portable executables for Windows and Linux can be found over in the releases section.

Example 1 - Bypassing a firewall

You'd like to connect from Host A to Host B, but a firewall is in the way. But both hosts have access to a shared folder.

Host A

ft.exe --tcp-listen 127.0.0.1:5000 --write "\\server\share\1.dat" --read "\\server\share\2.dat"

Host B

ft.exe --read "\\server\share\1.dat" --tcp-connect 127.0.0.1:3389 --write "\\server\share\2.dat"

Now on Host A, configure the client to connect to: 127.0.0.1:5000

Example 2 - Tunnel TCP through RDP (similar to SSH tunnel)

You'd like to connect to a remote service (eg. 192.168.1.50:8888), but only have access to Host B using RDP.

Host A

ft.exe --tcp-listen 127.0.0.1:5000 --write "C:\Temp\1.dat" --read "C:\Temp\2.dat"

Run an RDP client and ensure local drives are shared as shown here.

Connect to Host B.

Host B

ft.exe --read "\\tsclient\c\Temp\1.dat" --tcp-connect 192.168.1.50:8888 --write "\\tsclient\c\Temp\2.dat"

Now on Host A, you can connect to 127.0.0.1:5000 and it will be forwarded to 192.168.1.50:8888

How does it work?

The program starts a TCP listener, and when a connection is received it writes the TCP data into a file. This same file is read by the counterpart program, which establishes a TCP connection and onforwards the TCP data. To avoid the shared file growing indefinitely, it is purged whenever it gets larger than 10 MB.