def is_ip_address(host):
    """
    >>> is_ip_address('')
    False
    >>> is_ip_address('192.168.2.1')
    True
    >>> is_ip_address('192')
    False
    >>> is_ip_address('192.168')
    False
    >>> is_ip_address('192.168.2')
    False
    >>> is_ip_address('...')
    False
    >>> is_ip_address('asdf.asdf.asdf.asdf')
    False
    >>> is_ip_address('999.0.0.1')
    False
    """
    raw_parts = host.strip().split('.')
    parts = [p for p in raw_parts if p != '']
    if len(parts) != 4:
        return False
    else:
        for part in parts:
            if part.isdigit() and int(part) >= 0 and int(part) <= 255:
                pass
            else:
                return False
    return True