Here are some commands I ran on a freenas box to try to troubleshoot why I could not get a username after ssh'ing to the box as an active directory user.

freeNAS active directory troubleshooting

[root@freenas-test ~]# wbinfo -t
checking the trust secret for domain USERS via RPC calls succeeded

[root@freenas-test ~]# ssh ryant@localhost
Could not create directory '/root/.ssh'.
The authenticity of host 'localhost (127.0.0.1)' can't be established.
RSA key fingerprint is 54:7d:cc:9a:72:c4:9b:67:ea:bf:e4:f9:2c:97:fb:85.
Are you sure you want to continue connecting (yes/no)? yes
Failed to add the host to the list of known hosts (/root/.ssh/known_hosts).
ryant@localhost's password:
Last login: Wed Apr  3 10:23:13 2013 from 127.0.0.1
Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994
        The Regents of the University of California.  All rights reserved.

FreeBSD 8.3-RELEASE-p6 (FREENAS.i386) #0 r248141M: Sun Mar 10 23:42:41 PDT 2013

        FreeNAS (c) 2009-2013, The FreeNAS Development Team
        All rights reserved.
        FreeNAS is released under the modified BSD license.

        For more information, documentation, help or support, go here:
        http://freenas.org
Welcome to FreeNAS
[I have no name!@freenas-test ~]$
[I have no name!@freenas-test ~]$ whoami
8826
[I have no name!@freenas-test ~]$ ldapwhoami
SASL/GSSAPI authentication started
ldap_sasl_interactive_bind_s: Local error (-2)
        additional info: SASL(-1): generic failure: GSSAPI Error:  Miscellaneous failure (see text) (open(/tmp/krb5cc_8826): No such file or directory)
[I have no name!@freenas-test ~]$ getent passwd ryant
[I have no name!@freenas-test /mnt/test]$ wbinfo -t
checking the trust secret for domain USERS via RPC calls failed
failed to call wbcCheckTrustCredentials: WBC_ERR_WINBIND_NOT_AVAILABLE
Could not check secret
[I have no name!@freenas-test ~]$ exit
[root@freenas-test ~]# getent passwd ryant
ryant:*:8826:5:ryant:/home/ryant:/bin/bash