I need to fetch host name from ip address. Am able to fetch ip, mac addresses of all devices connected to my devices network, but hostname always returns nil.
i had tried below code snippets to retrieve hostname but it always returns nil in my network
CODE SNIPPET 1
+(NSString *)getHostFromIPAddress:(NSString*)ipAddress { struct addrinfo *result = NULL; struct addrinfo hints; memset(&hints, 0, sizeof(hints)); hints.ai_flags = AI_NUMERICHOST; hints.ai_family = PF_UNSPEC; hints.ai_socktype = SOCK_STREAM; hints.ai_protocol = 0; int errorStatus = getaddrinfo([ipAddress cStringUsingEncoding:NSASCIIStringEncoding], NULL, &hints, &result); if (errorStatus != 0) { return nil; } CFDataRef addressRef = CFDataCreate(NULL, (UInt8 *)result->ai_addr, result->ai_addrlen); if (addressRef == nil) { return nil; } freeaddrinfo(result); CFHostRef hostRef = CFHostCreateWithAddress(kCFAllocatorDefault, addressRef); if (hostRef == nil) { return nil; } CFRelease(addressRef); BOOL succeeded = CFHostStartInfoResolution(hostRef, kCFHostNames, NULL); if (!succeeded) { return nil; } NSMutableArray *hostnames = [NSMutableArray array]; CFArrayRef hostnamesRef = CFHostGetNames(hostRef, NULL); for (int currentIndex = 0; currentIndex < [(__bridge NSArray *)hostnamesRef count]; currentIndex++) { [hostnames addObject:[(__bridge NSArray *)hostnamesRef objectAtIndex:currentIndex]]; } return hostnames[0]; } CODE SNIPPET 2
#pragma mark - Get Host from IP +(NSString *)getHostFromIPAddress:(NSString*)ipAddress { struct addrinfo *result = NULL; struct addrinfo hints; memset(&hints, 0, sizeof(hints)); hints.ai_flags = AI_NUMERICHOST; hints.ai_family = PF_UNSPEC; hints.ai_socktype = SOCK_STREAM; hints.ai_protocol = 0; int error; struct addrinfo *results = NULL; error = getaddrinfo([ipAddress cStringUsingEncoding:NSASCIIStringEncoding], NULL, NULL, &results); if (error != 0) { NSLog (@"Could not get any info for the address"); return @""; // or exit(1); } for (struct addrinfo *r = results; r; r = r->ai_next) { char hostname[NI_MAXHOST] = {0}; error = getnameinfo(r->ai_addr, r->ai_addrlen, hostname, sizeof hostname, NULL, 0 , 0); if (error != 0) { continue; // try next one } else { return [NSString stringWithUTF8String:hostname];; NSLog (@"Found hostname: %s", hostname); break; } } freeaddrinfo(results); }