Subject Re: [firebird-support] GUID_CREATE() Node Identifier
Author Alexandre Benson Smith
Joe wrote:
> I am trying to troubleshoot an issue with a client, and I need to figure out which computer on the network is creating certain records. The table has a GUID as its key. I am using GUID_CREATE() from UUIDLIB.DLL with Firebird 1.
> I know that the last set of 12 digits is the node identifier, and it's supposed to be based on the MAC address. However, in doing a test myself, it doesn't seem to match the MAC address exactly.
> Is the MAC address somehow encoded or manipulated in some way before use in the GUID that is created?

I believe so... On the past MS implementation of UUID that is called
GUID does not encode the MAC Address, so it was possible to track down a
given GUID to a specific computer, that is the way the caught the
Melissa worm writer. This has been changed to protect personal identity.
All this is from the top of my head, so perhaps not 100% accurate...

> One other question... When used in a client-server situation, is the GUID based on the MAC address of the client, or the Firebird server?

I don't know the internals of the implementation, but I suppose FB makes
a system call to get the UUID/GUID, so this happens on the server side...

> -Joe

Alexandre Benson Smith
THOR Software e Comercial Ltda
Santo Andre - Sao Paulo - Brazil