Reachability reachabilityWithAddress does not work

I am trying to determine if the iphone can connect to my IP address using following code

struct sockaddr_in server_address;   
server_address.sin_len = sizeof(server_address);
server_address.sin_family = AF_INET;
server_address.sin_port = htons(8888);
server_address.sin_addr.s_addr = inet_addr("1.2.3.4");
Reachability *r = [[Reachability rea开发者_如何学编程chabilityWithAddress:&server_address ] retain];
NetworkStatus internetStatus = [r currentReachabilityStatus];

But it always says that the status is 'Reachable' regarless of what I give in the IP address. Am I doing anything wrong? Why won't this work? Thanks for your insight.

---

checkout this answer (https://stackoverflow.com/a/5875059/1067154)

SCNetworkReachability Reference

The SCNetworkReachability programming interface allows an application to determine the status of a system's current network configuration and the reachability of a target host.

A remote host is considered reachable when a data packet, sent by an application into the network stack, can leave the local device. Reachability does not guarantee that the data packet will actually be received by the host.