# Debug with UDP Listen

You may check the S2GW operation using UDP Listen running on S2GW.

The log contents is described in [udp\_listen\_log\_contents](https://help.boomerang3.com/s2gw-installation-manual/troubleshooting/udp_listen_log_contents "mention").

1. Open Terminal connection.
2. Enter:\
   \&#xNAN;*cd S2Gateway*\
   *./StartUDPListen.sh*

![](https://623241058-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F3O2JmRv8Cq2LTrIfpgxe%2Fuploads%2Fgit-blob-36868af1042c2b5aecd41cc2c6fd72c129b4cc85%2Fimage44.png?alt=media)

3. The UDP Listen log shall be displayed.
4. Use ^z to close UDP Listen and go back to command prompt.
5. The UDP Listen log is always saved to the SD card. It can be found in \
   /home/pi/S2Gateway/debug.log. When the file exceeds 10MB it is renamed to debug.log\_old and a new debug.log is created. If it happens again the previous debug.log\_old is overwritten.