# Option 1:
my $item_regex = qr/
 (?:int)\s+(\w+)\s*?\n
 (?:\s*Number\ of\ Flaps:\s(\d+)\s*?\n)?
 (?:\s*IP\sAddress:?\s([\d\.]+)\s*?\n)?
/x;

while (<DATA>) {
  if (/^$item_regex+\Z/) {
    print "$1, $2, $3\n" while (/\G$item_regex/g);
  }
}