Python check For network connection

Question

I want to know is there any python script (better a command) that can tell me am I connected to network or not.

I am not talking about "INTERNET", i'm talking about wired or wireless "NETWORK" (So please do not set this quetion as duplicate)

I mean my modem router is on and i'm connected to it (and it's not important it has internet or not) so the script returns True (It's better to not suggest terminal commands like ping etc.)

And also another question that might be an answer of this question: Is it good to get requests.get('192.168.1.1').status_code and if its 200 we're connected to a network?

Answer 1

And also another question that might be an answer of this question: Is it good to get requests.get('192.168.1.1').status_code and if its 200 we're connected to a network?

This isn't a great idea.

• What if the local network isn't 192.168.1.0/24 ?
• What if the gateway isn't 192.168.1.1 ?
• What if the router doesn't have an HTTP interface?

The only sane thing you can do is pick a well known endpoint (eg "google.com") and try to contact it (for example, requests.get("http://google.com") ). If it works...great, you're connected! If it doesn't work, you don't have enough information to decide if you're connected or not.

If you're only interested in local network connectivity, you could first determine your default gateway address (eg by running ip route under Linux, or route print on Windows), and then attempt to ping that. Once again, you can only detect a positive: if you get a response, you're connected, but if you don't, then you don't know whether you're connected or not.

Answer 2

everything that @larsks said is correct. additional You can check if You have an IP adress on Your host (or only localhost).

what You can do :

• check if You have an IP adress on Your box, which is different from localhost, loopback address range

• if You KNOW the default gateway (You can get it) You might ping the default gateway - but that might fail, because ICMP ping packets might be disabled on that default gateway.

to avoid TOCTOU Errors - just USE the adress and catch the errors ! (see: https://en.wikipedia.org/wiki/Time-of-check_to_time-of-use )

here the functions I use usually in that context:

def get_host_ip_or_localhost() -> Union[str, None]:
    """
    >>> result = get_host_ip_or_localhost()
    >>> assert is_valid_ip_adress(result)
    """
    host_ip = get_host_ip()

    if not host_ip:                                                                     # pragma: no cover
        logger.warning('can not get default gateway IP, setting localhost as IP')       # pragma: no cover
        host_ip = socket.gethostbyname('localhost')                                     # pragma: no cover
    return host_ip


def ip_is_localhost(host_ip: str) -> bool:
    """
    >>> ip_is_localhost('127.0.0.1')
    True
    >>> ip_is_localhost('localhost')
    True
    >>> ip_is_localhost('192.168.168.17')
    False
    >>> ip_is_localhost('192.168.168.254')
    False
    """
    host_ip = socket.gethostbyname(host_ip)
    local_host_ip = socket.gethostbyname('localhost')
    if host_ip == local_host_ip or host_ip.startswith('127.'):
        return True
    else:
        return False


def get_host_ip() -> Union[str, None]:
    """
    >>> result = get_host_ip()
    >>> assert is_valid_ip_adress(result)
    """
    o_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    # noinspection PyBroadException
    try:
        # doesn't even have to be reachable
        o_socket.connect(('1.1.1.1', 1))
        s_ip = str(o_socket.getsockname()[0])  # type: Union[str, None]
    except Exception:           # pragma: no cover
        s_ip = None             # pragma: no cover
    finally:
        o_socket.close()
    return s_ip


def is_internet_connected(ip_adress: str = '1.1.1.1') -> bool:
    """
    >>> is_internet_connected()
    True
    >>> is_internet_connected(ip_adress='www.un-kno-wn.com')
    False
    """
    response = lib_ping.ping(target=ip_adress, times=1)
    return bool(response.reached)


def is_valid_ip_adress(address: str) -> bool:
    """
    check if it is valid IPV4 or IPV6 Adress
    >>> is_valid_ip_adress('1.1.1.1')
    True
    >>> is_valid_ip_adress('::1')
    True
    >>> is_valid_ip_adress('unknown')
    False
    """
    if is_valid_ipv4_address(address) or is_valid_ipv6_address(address):
        return True
    else:
        return False


def is_valid_ipv4_address(address: str) -> bool:
    """
    >>> is_valid_ipv4_address('1.1.1.1')
    True
    >>> is_valid_ipv4_address('1.1.1.')
    False
    >>> is_valid_ipv4_address('unknown')
    False
    """
    try:
        socket.inet_pton(socket.AF_INET, address)
    except AttributeError:                      # pragma: no cover      # no inet_pton here, sorry
        try:                                    # pragma: no cover
            socket.inet_aton(address)           # pragma: no cover
        except socket.error:                    # pragma: no cover
            return False                        # pragma: no cover
        return address.count('.') == 3          # pragma: no cover
    except socket.error:                        # not a valid address
        return False

    return True


def is_valid_ipv6_address(address: str) -> bool:
    """
    >>> is_valid_ipv6_address('::1')
    True
    >>> is_valid_ipv6_address('127.0.0.1')
    False
    >>> is_valid_ipv6_address('unknown')
    False
    """
    try:
        socket.inet_pton(socket.AF_INET6, address)
    except socket.error:  # not a valid address
        return False
    return True