Net::IP solutions:

# for just DottedQuadToLong():
use Net::IP;
print Net::IP->new("24.72.30.83")->intip;

# for both directions:
use Net::IP qw/:PROC/;
print ip_bintoint(ip_iptobin("24.72.30.83",4));
print ip_bintoip(ip_inttobin("407379539",4),4);
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couple code comments:

• Personnally i'd write foreach (@quads) { $_ = hex } w/map: return join '.', map {hex} @quads;
• in DottedQuadToLong, the split is just extra work -- just capture each piece (don't need the substitution, either)

  sub DottedQuadToLong {
      my $ip_str = shift;
      return 0 unless $ip_str =~ /^\s*(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(
  +\d{1,3})\s*$/;
      my $ip = 0;
      foreach my $quad ($1,$2,$3,$4){
        return 0 if ($quad > 255);
        $ip = $ip * 256 + $quad;
      }
      return $ip;
  }
  [download]