ios_dns_lookup.m

#include <netdb.h>
#include <ifaddrs.h>
#include <arpa/inet.h>

+ (NSArray *)loopUpIPAddress:(NSURL *)url {
    NSMutableArray *ipAddrs = [[NSMutableArray alloc] init];
    
    char **pptr;
    struct hostent *_host = gethostbyname([[url host] UTF8String]);
    pptr = _host->h_addr_list;
    for (; *pptr != NULL; pptr++) {
        char ip_addr[32];
        inet_ntop(_host->h_addrtype, *pptr, ip_addr, sizeof(ip_addr));
        NSString* hostIP = [NSString stringWithUTF8String:ip_addr];
        [ipAddrs addObject:hostIP];
    }
    
    return [ipAddrs copy];
}