Redundant Load Balanced LDAP authentication fails when Primary is down

[tnt at kalik.net]

>I have two freeradius v2.1.3-1 servers setup to run with redundant load balancing with two Windows Active Directory LDAP servers for authentication.  When the LDAP servers are running the radius will load-balance between them and authenticate fine.  If I shut the primary LDAP server down radius doesn't authenticate properly against the second LDAP server.  I have tested the secondary LDAP as the the primary in the radius configuration and it works fine.  If I change the radius config to have a bogus primary name it will then authenticate with the secondary fine.  But when it has the correct name and the primary is down the authentication fails.  I believe it may have something to do with ntlm_auth but I don't understand why as in the other test instances with the bogus name it works.  Below is the LDAP portion of my server along with  a part of the debug of what happens when I shutdown the primary LDAP server.   If anyone has any suggestions it would be much appreciated. 
>

ntlm_auth is pointing to the first DC. If you give the bogus name DC is
still working (so does ntlm_auth). When you bring it down - ntlm_auth
stops working. You need to build in redundancy on the samba side. See
their documentation on how to configure backup DCs.

Ivan Kalik
Kalik Informatika ISP