How to get the external ip in Objective-C

Question

I looked for some code that will help me to get the ip that the iPhone connect with.

I find this one:

- (NSString *)getIPAddress
{
    NSString *address = @"error";
    struct ifaddrs *interfaces = NULL;
    struct ifaddrs *temp_addr = NULL;
    int success = 0;

    // retrieve the current interfaces - returns 0 on success
    success = getifaddrs(&interfaces);
    if (success == 0)
    {
        // Loop through linked list of interfaces
        temp_addr = interfaces;
        while(temp_addr != NULL)
        {
            if(temp_addr->ifa_addr->sa_family == AF_INET)
            {
                // Check if interface is en0 which is the wifi connection on the iPhone
                if([[NSString stringWithUTF8String:temp_addr->ifa_name] isEqualToString:@"en0"])
                {
                    // Get NSString from C String
                    address = [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)temp_addr->ifa_addr)->sin_addr)];
                }
            }

            temp_addr = temp_addr->ifa_next;
        }
    }

    // Free memory
    freeifaddrs(interfaces);

    return address;
}

but the problem is that he get me this ip 10.0.0.1

How to get the external ip?

Answer 1

The easiest way to get your internet ip address from code is to use NSURLConnection.

For the URL you can use: http://www.whatismyip.com/m/mobile.asp or http://checkip.dyndns.com/

Just parse the return data and you have your external ip address.

Answer 2

Have a look at the example in my second Answer here.

In a nutshell it uses *http://www.dyndns.org/cgi-bin/check_ip.cg*i to get the extenal I.P