By default, our redirector uses NTLMv2 authentication. Prior to joining your system to a Windows 2008 domain, please run the following command on your Solaris system such that NTLM authentication will be used instead:

sharectl set -p lmauth_level=2 smb

This is a known issue with Windows Server 2008 which by default disallows NTLMv2 authentication if the client doesn’t support extended security. Microsoft is working on a hot fix for this issue. Once it becomes available, the above workaround will no longer be needed.

Reference:

http://www.mail-archive.com/cifs-discuss@opensolaris.org/msg00170.html