Let the ESP8266 ping a remote machine.
With this library an ESP8266 can ping a remote machine and know if it's reachable. It provide some basic measurements on ping messages (avg response time).
First, include the library in your sketch along with WiFi library:
#include <ESP8266WiFi.h>
#include <ESP8266Ping.h>
Next, simply call the Ping.ping() function
IPAddress ip (192, 168, 0, 1); // The remote ip to ping
bool ret = Ping.ping(ip);
ret will be true if the remote responded to pings, false if not reachable.
The library supports hostname too, just pass a string instead of the ip address:
bool ret = Ping.ping("www.google.com");
Additionally, the function accept a second integer parameter count that specify how many pings has to be sent:
bool ret = Ping.ping(ip_or_host, 10);
After Ping.ping() has been called, the average response time (in milliseconds) can be retrieved with
int avg_time_ms = Ping.averageTime();