gtp_scan is a small python script that scans for GTP (GPRS tunneling protocol) speaking hosts. To discover those hosts it uses the GTP build in PING mechanism, it sends a GTP packet of the type ECHO_REQUEST and listens for an incoming GTP ECHO_REPLY. Its capable of generating ECHO_REQUESTS for GTP version 1 and GTP version 2. Also the script can scan for both, GTP-C and GTP-U (the control channel and the user data channel), only the port differs here.
In the output the received packet is displayed and the basic GTP header is dissected so one can see a GTP version 1 host answering a GTP version 2 ECHO_REQUEST with the ‘version not supported’ message.
Tests have shown that there are some strange services around, which answer to an GTP ECHO_REQUEST with a lot of weird data, which leads to ‘kind of’ false positive results but they can easily be discovered by checking the output data with your brain 😉 (eg. there is no GTP version 12)
download it here gtp_scan-0.5.tar.gz
enjoy
/daniel