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astrashe · Jan 31, 2005, 11:18 PM

I just wiped off my disk and reinstalled the OS, then reinstalled Ulysses with a trial license. Ulysses was able to tell it was on the same machine -- instead of a 30 day license, it gave me 27 days.

That's fine, it's the terms of the deal with Ulysses and I can't complain, but I'm curious about how Ulysses did it. Is there a unique ID number tied to the hardware that programs can run (sort of like the ID numbers Intel put into its processors), or did the software just assume it was the same because I have a reasonably static IP address?

Big Mac · Feb 1, 2005, 01:07 AM

If you reformatted your hard drive and reinstalled everything fresh, which would be rather odd, then I would be interested to know how the program determined it had been run before. But if you restored your Home folder from a backup, then a preference file or another invisible file tracking registration would be in your Library some place. The only thing that is similar to Intel's processor code scheme on the Mac would be the Ethernet MAC ID, which is something every ethernet card has.

astrashe · Feb 1, 2005, 01:49 AM

Originally posted by Big Mac:
If you reformatted your hard drive and reinstalled everything fresh, which would be rather odd, then I would be interested to know how the program determined it had been run before. But if you restored your Home folder from a backup, then a preference file or another invisible file tracking registration would be in your Library some place. The only thing that is similar to Intel's processor code scheme on the Mac would be the Ethernet MAC ID, which is something every ethernet card has.

I did reformat the entire drive. I'm new to macs, and have an old G3 iMac that I'm playing with. I wiped off the drive to repartion it, and inbetween the two OS X installations I had Ubuntu Linux on the machine. I didn't restore my home directory, as I didn't have anything important in it.

I figure that it must have used the IP address. It talks to a server to get the license, so it's the most logical explanation. It was just a little odd.

Sarc · Feb 1, 2005, 05:04 AM

iTunes has remembered my playlists on 2 different Macs, with different OS, on a total of 3 full drive formats.

There must be a way I guess ... PRAM ?

Maflynn · Feb 1, 2005, 08:10 AM

Perhaps this app phones home? are you connected to net via broadband?

-Q- · Feb 1, 2005, 09:03 AM

Originally posted by astrashe:

I figure that it must have used the IP address. It talks to a server to get the license, so it's the most logical explanation. It was just a little odd.

If it talks to a server to get the license, then it's probably your computer's MAC address (which stands for Media Access Control, not Macintosh). The MAC address is a unique identifier for your networking port and every computer has one. The Ulysses server probably keeps records of the mac address used to request the license, so it knew you'd requested one 3 days ago.

astrashe · Feb 1, 2005, 11:31 AM

Originally posted by Sarc:
iTunes has remembered my playlists on 2 different Macs, with different OS, on a total of 3 full drive formats.

There must be a way I guess ... PRAM ?

That's pretty wild -- did you login to the store, or set up an online ID? (I haven't used iTunes, so if those are dumb questions, I'm sorry.)

astrashe · Feb 1, 2005, 11:32 AM

Originally posted by Maflynn:
Perhaps this app phones home? are you connected to net via broadband?

It definitely phones home -- it goes out and asks a server for a temporary license. But I still don't know how it knows that this copy of my OS X is on the same machine as the last copy.

astrashe · Feb 1, 2005, 11:40 AM

Originally posted by -Q-:
If it talks to a server to get the license, then it's probably your computer's MAC address (which stands for Media Access Control, not Macintosh). The MAC address is a unique identifier for your networking port and every computer has one. The Ulysses server probably keeps records of the mac address used to request the license, so it knew you'd requested one 3 days ago.

I'm pretty sure that the MAC address information doesn't get encoded in the TCP/IP packets -- it would be used on the local LAN for communication between my gateway and my computer, but it wouldn't be transmitted out into the net at large.

Having said that, a program running on my iMac would probably be able to read the MAC addresses on my network adapters (I have an airport card, which I'm using, and a built in ethernet adapter, which I'm not), and use those as machine specific identifiers.

So maybe it reads the MAC address from the built in ethernet port (which would always be there on a Macintosh) and transmits it to the licensing server.

tooki · Feb 1, 2005, 02:40 PM

Well, this is HIGHLY unlikely, but it could (if it requires an admin password to install) write to the NVRAM, which allows the addition of arbitrary data (without interfering with booting in any way). So it is possible that it could save it off-disk.

One way to test this would be to do an NVRAM reset by booting while holding Command-Option-P-R, or Command-Option-O-F and then typing:
reset-nvram [enter]
reset-all [enter]

tooki

Sarc · Feb 1, 2005, 07:25 PM

Originally posted by astrashe:
That's pretty wild -- did you login to the store, or set up an online ID? (I haven't used iTunes, so if those are dumb questions, I'm sorry.)

no
and no

it just remembered the playlists ... and since I mantained the same location for MP3 as before the format, I was able to use the playlists with no problems at all.

macmike42 · Feb 2, 2005, 08:58 AM

Originally posted by astrashe:
I'm pretty sure that the MAC address information doesn't get encoded in the TCP/IP packets -- it would be used on the local LAN for communication between my gateway and my computer, but it wouldn't be transmitted out into the net at large.

This is not true. If you have a router, your router's MAC address is included in every packet, if your machine is directly connected, your machine's MAC address will be.

TCP/IP is a software networking layer that uses IP addresses to figure out which packets go where, and it sits on top of Ethernet, which is a hardware networking layer that uses MAC addresses to figure out which packets go where.

You can change the MAC address of any network card (wired or wireless) via the BSD ifconfig command, but I wouldn't recommend it, plus it may be next to impossible with any consumer router.

To answer your question, yes, it is almost certainly the MAC address that was used to "nail down" your license.

Also, not that it would stop anyone, but don't you need to be root to write to NVRAM?

astrashe · Feb 2, 2005, 07:29 PM

Originally posted by macmike42:
This is not true. If you have a router, your router's MAC address is included in every packet, if your machine is directly connected, your machine's MAC address will be.

I don't claim to be a networking layer guru, but I don't see a MAC address in the TCP/IP header:

http://www.networksorcery.com/enp/protocol/ip.htm

macmike42 · Feb 2, 2005, 10:16 PM

Um, it says right on that page:
MAC Header -> IP Header -> Data

Guess which one of those contains the other and, along with it, the MAC address?