% perl -MFirefox::Marionette -e 'my $f=Firefox::Marionette->new()'
Undefined address for Socket::pack_sockaddr_in at /Users/<user>/perl5/lib/perl5/Firefox/Marionette.pm line 7134.

##</code><code>##

    $sock_addr =
      Socket::pack_sockaddr_in( $port, Socket::inet_aton($host) );

##</code><code>##

% perl -MSocket -e'defined (my $a=inet_aton("garbage")) or die"dead"; print unpack "V", $a;'
dead at -e line 1.
% perl -MSocket -e'defined (my $a=inet_aton("127.0.0.1")) or die"dead"; print unpack "V", $a;'
16777343