postinst is in zentyal-openvpn 2.3.10+quantal1.
This file is a maintainer script. It is executed when installing (*inst) or removing (*rm) the package.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | #!/bin/bash
set -e
case "$1" in
    configure)
        # initial setup
        /usr/share/zentyal/initial-setup --no-restart openvpn $2
        # restart module
        invoke-rc.d zentyal openvpn restart || true
        dpkg-trigger --no-await zentyal-core
    ;;
esac
exit 0
 |