How do I check for a network connection?
You can check for a network connection in .NET 2.0 using GetIsNetworkAvailable()
:
System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable()
To monitor changes in IP address or changes in network availability use the events from the NetworkChange class:
System.Net.NetworkInformation.NetworkChange.NetworkAvailabilityChanged
System.Net.NetworkInformation.NetworkChange.NetworkAddressChanged
How can I see if there's an available and active network connection in Python?
Perhaps you could use something like this:
import urllib2
def internet_on():
try:
urllib2.urlopen('http://216.58.192.142', timeout=1)
return True
except urllib2.URLError as err:
return False
Currently, 216.58.192.142 is one of the IP addresses for google.com. Change http://216.58.192.142
to whatever site can be expected to respond quickly.
This fixed IP will not map to google.com forever. So this code is
not robust -- it will need constant maintenance to keep it working.
The reason why the code above uses a fixed IP address instead of fully qualified domain name (FQDN) is because a FQDN would require a DNS lookup. When the machine does not have a working internet connection, the DNS lookup itself may block the call to urllib_request.urlopen
for more than a second. Thanks to @rzetterberg for pointing this out.
If the fixed IP address above is not working, you can find a current IP address for google.com (on unix) by running
% dig google.com +trace
...
google.com. 300 IN A 216.58.192.142
What is the best way to check for Internet connectivity using .NET?
public static bool CheckForInternetConnection(int timeoutMs = 10000, string url = null)
{
try
{
url ??= CultureInfo.InstalledUICulture switch
{
{ Name: var n } when n.StartsWith("fa") => // Iran
"http://www.aparat.com",
{ Name: var n } when n.StartsWith("zh") => // China
"http://www.baidu.com",
_ =>
"http://www.gstatic.com/generate_204",
};
var request = (HttpWebRequest)WebRequest.Create(url);
request.KeepAlive = false;
request.Timeout = timeoutMs;
using (var response = (HttpWebResponse)request.GetResponse())
return true;
}
catch
{
return false;
}
}
Android check internet connection
This method checks whether mobile is connected to internet and returns true if connected:
private boolean isNetworkConnected() {
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
return cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected();
}
in manifest,
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
Edit:
This method actually checks if device is connected to internet(There is a possibility it's connected to a network but not to internet).
public boolean isInternetAvailable() {
try {
InetAddress ipAddr = InetAddress.getByName("google.com");
//You can replace it with your name
return !ipAddr.equals("");
} catch (Exception e) {
return false;
}
}
Check network connection android
It's better to (1) pass in the context so that the every activity can invoke this functions, and (2) Make this function static:
public boolean isNetworkOnline() {
boolean status=false;
try{
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getNetworkInfo(0);
if (netInfo != null && netInfo.getState()==NetworkInfo.State.CONNECTED) {
status= true;
}else {
netInfo = cm.getNetworkInfo(1);
if(netInfo!=null && netInfo.getState()==NetworkInfo.State.CONNECTED)
status= true;
}
}catch(Exception e){
e.printStackTrace();
return false;
}
return status;
}
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