1)  On systems running Upstart, shorewall-init cannot reliably secure
    the firewall before interfaces are brought up.

2)  Beginning with 4.4.16, compilation will fail if an empty shell
    variable was referenced in a config file on a system where /bin/sh
    is the Bourne Again Shell (bash).

    Corrected in 4.4.16.1.

3)  Startup can fail on a system where module autoloading is not
    available and where TC_ENABLED=Simple is specified in
    shorewall.conf.

    Workaround: 

    If LOAD_HELPERS_ONLY=No,

       a) Copy /usr/share/shorewall/modules to /etc/shorewall/
       b) Add 'loadmodule sch_prio' to the copy

    If LOAD_HELPERS_ONLY=Yes,

       a) Copy /usr/share/shorewall/helpers to /etc/shorewall/
       b) Add 'loadmodule sch_prio' to the copy