How can I programmatically get the MAC address of an iphone

NOTE As of iOS7, you can no longer retrieve device MAC addresses. A fixed value will be returned rather than the actual MAC

Somthing I stumbled across a while ago. Originally from here I modified it a bit and cleaned things up.

IPAddress.h
IPAddress.c

And to use it

InitAddresses();
GetIPAddresses();
GetHWAddresses();

int i;
NSString *deviceIP = nil;
for (i=0; i<MAXADDRS; ++i)
{
    static unsigned long localHost = 0x7F000001;        // 127.0.0.1
    unsigned long theAddr;

    theAddr = ip_addrs[i];

    if (theAddr == 0) break;
    if (theAddr == localHost) continue;

    NSLog(@"Name: %s MAC: %s IP: %s\n", if_names[i], hw_addrs[i], ip_names[i]);

        //decided what adapter you want details for
    if (strncmp(if_names[i], "en", 2) == 0)
    {
        NSLog(@"Adapter en has a IP of %s", ip_names[i]);
    }
}

Adapter names vary depending on the simulator/device as well as wifi or cell on the device.

This looks like a pretty clean solution: UIDevice BIdentifier

// Return the local MAC addy
// Courtesy of FreeBSD hackers email list
// Accidentally munged during previous update. Fixed thanks to erica sadun & mlamb.
- (NSString *) macaddress{

    int                 mib[6];
    size_t              len;
    char                *buf;
    unsigned char       *ptr;
    struct if_msghdr    *ifm;
    struct sockaddr_dl  *sdl;

    mib[0] = CTL_NET;
    mib[1] = AF_ROUTE;
    mib[2] = 0;
    mib[3] = AF_LINK;
    mib[4] = NET_RT_IFLIST;

    if ((mib[5] = if_nametoindex("en0")) == 0) {
        printf("Error: if_nametoindex error\n");
        return NULL;
    }

    if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 1\n");
        return NULL;
    }

    if ((buf = malloc(len)) == NULL) {
        printf("Could not allocate memory. error!\n");
        return NULL;
    }

    if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 2");
        free(buf);
        return NULL;
    }

    ifm = (struct if_msghdr *)buf;
    sdl = (struct sockaddr_dl *)(ifm + 1);
    ptr = (unsigned char *)LLADDR(sdl);
    NSString *outstring = [NSString stringWithFormat:@"%02X:%02X:%02X:%02X:%02X:%02X", 
                           *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];
    free(buf);

    return outstring;
}

@Grantland This "pretty clean solution" looks similar to my own improvement over iPhoneDeveloperTips solution.

You can see my step here: https://gist.github.com/1409855/

/* Original source code courtesy John from iOSDeveloperTips.com */

#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>

+ (NSString *)getMacAddress
{
    int                 mgmtInfoBase[6];
    char                *msgBuffer = NULL;
    NSString            *errorFlag = NULL;
    size_t              length;

    // Setup the management Information Base (mib)
    mgmtInfoBase[0] = CTL_NET;        // Request network subsystem
    mgmtInfoBase[1] = AF_ROUTE;       // Routing table info
    mgmtInfoBase[2] = 0;              
    mgmtInfoBase[3] = AF_LINK;        // Request link layer information
    mgmtInfoBase[4] = NET_RT_IFLIST;  // Request all configured interfaces

    // With all configured interfaces requested, get handle index
    if ((mgmtInfoBase[5] = if_nametoindex("en0")) == 0) 
        errorFlag = @"if_nametoindex failure";
    // Get the size of the data available (store in len)
    else if (sysctl(mgmtInfoBase, 6, NULL, &length, NULL, 0) < 0) 
        errorFlag = @"sysctl mgmtInfoBase failure";
    // Alloc memory based on above call
    else if ((msgBuffer = malloc(length)) == NULL)
        errorFlag = @"buffer allocation failure";
    // Get system information, store in buffer
    else if (sysctl(mgmtInfoBase, 6, msgBuffer, &length, NULL, 0) < 0)
    {
        free(msgBuffer);
        errorFlag = @"sysctl msgBuffer failure";
    }
    else
    {
        // Map msgbuffer to interface message structure
        struct if_msghdr *interfaceMsgStruct = (struct if_msghdr *) msgBuffer;

        // Map to link-level socket structure
        struct sockaddr_dl *socketStruct = (struct sockaddr_dl *) (interfaceMsgStruct + 1);

        // Copy link layer address data in socket structure to an array
        unsigned char macAddress[6];
        memcpy(&macAddress, socketStruct->sdl_data + socketStruct->sdl_nlen, 6);

        // Read from char array into a string object, into traditional Mac address format
        NSString *macAddressString = [NSString stringWithFormat:@"%02X:%02X:%02X:%02X:%02X:%02X",
                                      macAddress[0], macAddress[1], macAddress[2], macAddress[3], macAddress[4], macAddress[5]];
        NSLog(@"Mac Address: %@", macAddressString);

        // Release the buffer memory
        free(msgBuffer);

        return macAddressString;
    }

    // Error...
    NSLog(@"Error: %@", errorFlag);

    return nil;
}