Obtaining a server IP address from hostname - objective-c

Question

When performing an NSURLRequest to a hostname, is it possible to obtain the IP address of the server that the response came from?
The NSURL method:
- (NSString *)host;
simply returns the hostname, and I see no way of obtaining the IP address from any of the other NSURL methods.
Perhaps there is a way of performing a host lookup before inititing the NSURLRequest?

Answer 1

You can use the system call gethostbyname() to resolve a hostname then use the returning structure to get the ip address. Have a look at inet_ntop() for this last part.
EXAMPLE CODE
struct hostent *hostentry;
hostentry = gethostbyname("google.com");
char * ipbuf;
ipbuf = inet_ntoa(*((struct in_addr *)hostentry->h_addr_list[0]));
printf("%s",ipbuf);

Answer 2

I was asking a question regarding
"how to get IP from hostname in unix\linux?"
but found this question in a different context which is not for Unix I guess, let me correct if I am wrong
since this question already been asked so I am fearing to avoid asking the same question marked as duplicated by stack overflow team.
Quest: how to get IP from hostname in unix\linux?
Ans: the two commands over there
ping host_name
Ex:
ping -s google.co.in
PING google.co.in: 56 data bytes
64 bytes from dfw06s48-in-f3.1e100.net (216.58.194.99): icmp_seq=0. time=2.477 ms
64 bytes from dfw06s48-in-f3.1e100.net (216.58.194.99): icmp_seq=1. time=1.415 ms
64 bytes from dfw06s48-in-f3.1e100.net (216.58.194.99): icmp_seq=2. time=1.712 ms
nslookup host_name
Ex:
nslookup google.co.in
Server: 155.179.59.249
Address: 155.179.59.249#53
Non-authoritative answer:
Name: google.co.in
Address: 216.58.194.99

Answer 3

#import <arpa/inet.h>
- (BOOL)resolveHost:(NSString *)hostname {
Boolean result;
CFHostRef hostRef;
CFArrayRef addresses;
NSString *ipAddress = nil;
hostRef = CFHostCreateWithName(kCFAllocatorDefault, (__bridge
CFStringRef)hostname);
CFStreamError *error = NULL;
if (hostRef) {
result = CFHostStartInfoResolution(hostRef, kCFHostAddresses, error);
if (result) {
addresses = CFHostGetAddressing(hostRef, &result);
}
}
if (result) {
CFIndex index = 0;
CFDataRef ref = (CFDataRef) CFArrayGetValueAtIndex(addresses, index);
int port=0;
struct sockaddr *addressGeneric;
NSData *myData = (__bridge NSData *)ref;
addressGeneric = (struct sockaddr *)[myData bytes];
switch (addressGeneric->sa_family) {
case AF_INET: {
struct sockaddr_in *ip4;
char dest[INET_ADDRSTRLEN];
ip4 = (struct sockaddr_in *)[myData bytes];
port = ntohs(ip4->sin_port);
ipAddress = [NSString stringWithFormat:#"%s", inet_ntop(AF_INET, &ip4->sin_addr, dest, sizeof dest)];
}
break;
case AF_INET6: {
struct sockaddr_in6 *ip6;
char dest[INET6_ADDRSTRLEN];
ip6 = (struct sockaddr_in6 *)[myData bytes];
port = ntohs(ip6->sin6_port);
ipAddress = [NSString stringWithFormat:#"%s", inet_ntop(AF_INET6, &ip6->sin6_addr, dest, sizeof dest)];
}
break;
default:
ipAddress = nil;
break;
}
}
NSLog(#"%#", ipAddress);
if (ipAddress) {
return YES;
} else {
return NO;
}
}
[self resolveHost:#"google.com"]