There are a couple of connectivity issues related to using a Macintosh in a Windows network that are worth noting. These can impact connectivity of both Mac OS 10.4 and 10.5 in an SBS (or other Active Directory network).

First, if the Active Directory login name matches either the Full Name or shortname of a local Macintosh account, you will not be able to authenticate against active directory. What seems to be happening in this instance is that the Mac OS authentication mechanism looks first at the local user directory before looking at any remote user directories when attempting authentication. If the name entered at login matches an accoun in the local user directory, Mac OS will attempt to authenticate against that user instead of the account in the remote user directory. This means an AD account named “jane” will not authenticate against AD if there is a local account with the shortname “jane” or the long name “Jane Dough.” Even if the shortname for “Jane Dough” is “admin,” the authentication will fail.

To resolve this issue, first create another local Mac user account with a long name and short name that have no close matches to any account in Active Directory. Make that user an administrator over the local machine. Then log in with that new user and remove any local accounts with names similar to the AD login name. If the user has been using that local account for a while, you will need to take steps to move the local user profile information into another account, which is not a trivial task. Only after you delete the local account with a similar name to the AD account will you be able to authenticate against the AD account. This happens whether you join the Mac to Active Directory or not.

Second, I have seen two instances where joining a fresh Leopard (10.5) install to an SBS network have been problematic. Specifically, when you log in with AD credentials, the process can take 5 or more minutes to process the login. Unfortunately, I have not been able to troubleshoot these two instances the way I had wanted, and I have not been able to replicate the behavior on demand. I believe that there is an issue/delay with the Mac doing LDAP lookups in AD to get the account information for authentication, but I cannot be sure withouth further testing.

If anyone has seen this problem and is willing to work with me to do some more in-depth troubleshooting on the problem, please let me know. Given the number of systems that I’ve connected and that have been done following the instructions on this blog and the smallbizserver.net site, this specific behavior is very rare. But now that I’ve seen it twice, I’d like to know what’s going on and modify these instructions as needed to help prevent that problem in the future.