Reachability - for local LAN IP address

Question

I am trying to check the reachability of a device on WIFI

I have modified code from Maher Ali's book "Advanced IOS4 Programming" to use an IP address as follows

- (BOOL) networkConnected: (NSString *) addr {
SCNetworkReachabilityFlags  flags = 0;
SCNetworkReachabilityRef    netReachability;
BOOL                        retrievedFlags = NO;

// added the "if" and first part of if statement
//
if (hasLeadingNumberInString(addr)) {
    struct sockaddr_in the_addr;
    memset((void *)&the_addr, 0, sizeof(the_addr));
    the_addr.sin_family = AF_INET;
    the_addr.sin_port = htons(1001);
    const char* server_addr = [addr UTF8String];
    unsigned long ip_addr = inet_addr(server_addr);
    the_addr.sin_addr.s_addr = ip_addr;
    netReachability =    SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (struct sockaddr*)&the_addr);      
} else {
    netReachability = SCNetworkReachabilityCreateWithName(kCFAllocatorDefault, [addr UTF8String]);
}   
if (netReachability) {
    retrievedFlags = SCNetworkReachabilityGetFlags(netReachability, &flags);
    CFRelease(netReachability);
}
if (!retrievedFlags || !flags) {
    return NO;
}
return YES;
}

But it always returns NO using an IP address and port that I know I can connect to (ie if I skip this check, all goes well)

I am trying to connect to "10.0.0.59" port 1001 which I can do

it does compile - and I have stepped (on an ipod) through and it is running through the socket section of the code.

netReachability is returned as zero.

relevant headers included are

#import "Reachability.h"
#include <CFNetwork/CFSocketStream.h>
#include <arpa/inet.h>

Can anybody spot what I am doing wrong?

Answer 1

I use Tony Million's newer Reachability that makes stuff like this very easy. To do this you could just do something like:

if([[Reachability reachabilityForLocalWiFi] isReachable]) {
    // It's reachable on wifi
}

Answer 2

Not sure if this help but I use Reachability.h from apple everytime I want to check if the app is connected to internet(or any internal IP)

here is my code

#import "Reachability.h"



if([[Reachability sharedReachability] internetConnectionStatus] == NotReachable) {
        UIAlertView *myAlert = [[UIAlertView alloc] initWithTitle:@"No Internet Connection" message:@"You require an internet connection via WiFi or cellular network for location finding to work." delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil];
        [myAlert show];
        [myAlert release];
}else{
        // Do something 
}