(Objective-C) Check Internet Connectivity

Demonstrates an efficient way to test for Internet connectivity.

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

#import <CkoSocket.h>
#import <NSString.h>

BOOL success = NO;

CkoSocket *socket = [[CkoSocket alloc] init];
// 1. Use a reliable Anycast IP. 
//    8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) are the industry standards.
NSString *targetIp = @"8.8.8.8";

// 2. Use Port 53 (DNS). 
//    DNS servers typically listen on TCP Port 53 as well as UDP. 
//    (Alternatively, use port 443 if you suspect port 53 is blocked).
int port = 53;

// 3. Disable SSL (0). 
//    We are not doing a handshake, just a TCP connection.
BOOL ssl = NO;

// 4. Short Timeout (1500ms).
//    If you can't reach Google in 1.5 seconds, the connection is 
//    likely too poor for practical use anyway.
int timeoutMs = 1500;

// Connect
success = [socket Connect: targetIp port: [NSNumber numberWithInt: port] ssl: ssl maxWaitMs: [NSNumber numberWithInt: timeoutMs]];
if (success == NO) {
    NSLog(@"%@",socket.LastErrorText);
    return;
}

[socket Close: [NSNumber numberWithInt: 10]];

NSLog(@"%@",@"We have Internet connectivity.");