$ ./ping.pl -N 123.321.12 -ptcp
123.321.12.0 is not alive
123.321.12.1 is not alive
^C
// script seemed to hang 

$ ./ping.pl -N 123.321.12 -pudp
123.321.12.0 is not alive
123.321.12.1 is not alive
123.321.12.2 is not alive
123.321.12.3 is not alive
123.321.12.4 is not alive
123.321.12.5 is not alive
123.321.12.6 is not alive
123.321.12.7 is not alive
... 
123.321.12.254 is not alive

$ ./ping.pl -N 123.321.12   
icmp ping requires root privilege at ./ping.pl line 21