Maximum number of connections are impacted by certain limits on both client & server sides, albeit a little differently. On the client side: Increase the ephermal port range, and decrease the tcp_fin_timeout To find out the default values: sysctl net.ipv4.ip_local_port_range sysctl net.ipv4.tcp_fin_timeout The ephermal port range defines the maximum number of outbound sockets a host … Read more
Summary A TCP socket is an endpoint instance defined by an IP address and a port in the context of either a particular TCP connection or the listening state. A port is a virtualisation identifier defining a service endpoint (as distinct from a service instance endpoint aka session identifier). A TCP socket is not a … Read more
If you know what port the process is running you can type: lsof -i:<port>. For instance, lsof -i:8080, to list the process (pid) running on port 8080. Then kill the process with kill <pid>
On Linux, see netem: the kernel already contains support for traffic shaping, and can simulate high latency, low bandwidth, packet losses, and all sort of other adverse conditions, even on a loopback device (so you don’t need a real, physical network to test across).
I was unable to get @Factor Mystic’s answer to work with POSIX regular expressions, so I wrote one that works with POSIX regular expressions and PERL regular expressions. It should match: IPv6 addresses zero compressed IPv6 addresses (section 2.2 of rfc5952) link-local IPv6 addresses with zone index (section 11 of rfc4007) IPv4-Embedded IPv6 Address (section … Read more
You can instruct curl to use the HTTP HEAD method via CURLOPT_NOBODY. More or less $ch = curl_init(“http://www.example.com/favicon.ico”); curl_setopt($ch, CURLOPT_NOBODY, true); curl_exec($ch); $retcode = curl_getinfo($ch, CURLINFO_HTTP_CODE); // $retcode >= 400 -> not found, $retcode = 200, found. curl_close($ch); Anyway, you only save the cost of the HTTP transfer, not the TCP connection establishment and closing. … Read more
This generally means that the remote side closed the connection (usually by sending a TCP/IP RST packet). If you’re working with a third-party application, the likely causes are: You are sending malformed data to the application (which could include sending an HTTPS request to an HTTP server) The network link between the client and server … Read more
I’m hoping someone can provide some concrete examples of best use cases for each. Use Retrofit if you are communicating with a Web service. Use the peer library Picasso if you are downloading images. Use OkHTTP if you need to do HTTP operations that lie outside of Retrofit/Picasso. Volley roughly competes with Retrofit + Picasso. … Read more
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 … Read more
There is no TCP API that will tell you the current state of the connection. isConnected() and isClosed() tell you the current state of your socket. Not the same thing. isConnected() tells you whether you have connected this socket. You have, so it returns true. isClosed() tells you whether you have closed this socket. Until … Read more