- (NSString*)defaultRouter {

    SCDynamicStoreRef ds = SCDynamicStoreCreate(kCFAllocatorDefault, CFSTR("myApplication"), NULL, NULL);
    CFDictionaryRef dr6 = SCDynamicStoreCopyValue(ds, CFSTR("State:/Network/Global/IPv6"));
    CFDictionaryRef dr4 = SCDynamicStoreCopyValue(ds, CFSTR("State:/Network/Global/IPv4"));
    if(dr6)
      {
        CFStringRef router = CFDictionaryGetValue(dr6, CFSTR("PrimaryInterface"));
        NSString *routerString = [NSString stringWithString:(__bridge NSString *)router];
        self.primaryInterface=routerString;
           return self.primaryInterface;
                CFRelease(dr6);

      }
    else if(dr4)
      {

        CFStringRef router = CFDictionaryGetValue(dr4, CFSTR("PrimaryInterface"));
        NSString *routerString = [NSString stringWithString:(__bridge NSString *)router];
        NSLog(@"%@", routerString);
        self.primaryInterface=routerString;
           return self.primaryInterface;
                CFRelease(dr4);
      }
    CFRelease(ds);
    return 0;

  }

SCNetworkInterfaceGetLocalizedDisplayName(primaryInterface)