my $dotted_quad = do {
    my $allowed_numbers = join '|', 0 .. 255;
    my $quad = qr/(?: $allowed_numbers )/x
    qr/ $quad \. $quad \. $quad \. $quad /x;
};

. . . 
if( $ipadd =~ /($dotted_quad)/ ) {
    $ipaddress = $1;
}