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Perl Fast IP Lookup
This uses /etc/hosts and local named cache, before using DNS
Thus if the host is already known it will report it almost instantally!

  perl -le 'print join(".", unpack("C4",(gethostbyname(shift))[4]))' `hostname`
OR
  perl -e 'printf "%vd\n",(gethostbyname("'"$Machine"'"))[4]'


Fast reverse lookup (can be faked by hacker)

  perl -MSocket -le 'print((gethostbyaddr(pack("C4",split("\\.",shift)),AF_INET))[0])' 132.234.250.63

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IP conversions.

IP byte form to Number
  perl -le 'print unpack("N", 127.0.0.1)'

IP string to Byte form, to Number
  perl -MSocket -le 'print unpack("N", inet_aton("127.0.0.1"))'

Number to IP string
  perl -MSocket -le 'print inet_ntoa(pack("N", 2130706433))'

Alturnative ( $, = '.' is array element separator on pint)
  perl -le '$ip = 2130706433;  $, = ".";
            print map { (($ip>>8*($_))&0xFF) } reverse 0..3'


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Perl Network Broadcast...

$port = 8080;
$sockaddr = "S n a4 x8";($name,$aliases,$proto) = getprotobyname('udp');

chop($hostname = `hostname`);
($name,$aliases,$type,$len,$myaddr) = gethostbyname($hostname);
@myaddr=unpack("C4",$myaddr);
pop(@myaddr);push(@myaddr,255); # works only for ff:ff:ff:00 subnet mask
$broadaddr=pack("C4",@myaddr);

$me   = pack($sockaddr,&AF_INET, 0,     $myaddr);
$them = pack($sockaddr,&AF_INET, $port, $broadaddr);

socket(S, &AF_INET, &SOCK_DGRAM, $proto) || die $!;
setsockopt(S,&SOL_SOCKET,&SO_BROADCAST,1) || die $1;
bind(S, $me) || die $!;

send(S,"01234567 Hello everyone 01234567\n",0,$them) || die $!;

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