I think this was easy to find, but I was really happy to find this kb article late last night. If you haven’t installed 2003 R2 before, it’s basically a 2003 install with a 2nd CD that installs the R2 parts. The cool part about this is you can upgrade a 2003 server to R2 with just the 2nd CD. The article has a bunch of edge cases but basically if you have 2003 SPx Standard, you can upgrade to R2 just by running the setup on the 2nd R2 CD. It’s worth noting that the install warned that I would not be able to uninstall the service pack after the upgrade.
I had a server that needed to be R2 as it was x64 and someone else had built it, installed updates, done the dcpromo, etc. I had to be R2 as SFU (Services For Unix) won’t install on x64. I tried. It said no. Fortunately R2 has parts of SFU built in, rebranded as Identity Management for Unix. Upgrading to/Installing R2 x64 was pretty easy, except that I got nervous when a .NET Framework child install took forever and provided no progress indication.
R2 provides RFC2307 compliantish schema updates that allow putting uid/gid/shell/etc into LDAP. There’s even an ADUC tab called “Unix Attributes”, but I didn’t see anything more enterprise. It just assigns the next available uid starting at 10,000 out of the box. It’s really part of this “NIS Server” functionality, so if you’re a NIS shop it may be easy to tie the bits together. DO NOT Install ‘Password Synchronization’. You don’t need it for NIS/LDAP, and it appears you have to demote to remove it.