My Jenkins Continuous Integration Server is on running on a Ubuntu host, configured as follows:
Create a logger with trace level logging for the com.cloudbees.jenkins
category under your /log
url (Manage Jenkins-> System logs).
Verify that there is a Webhook URL entry under the Service Hooks section of your repository administration screen.
Click test hook and you should see some log activity under your newly created logger.
Finally, check the GitHub Polling log action on the build which you have configured to be triggered by GitHub pushes.
A common mistake is testing commit hooks like this without having a change present.
The hook is only used to prompt a poll and won't perform a build unless changes are detected.