Client machine authentication falling back to NTLM.

  • Thread starter Thread starter Dennis Tighe
  • Start date Start date
D

Dennis Tighe

We have a Windows 2003 Member Server which is having some funky
problems. It seems that every time a computer attempts to authenticate
to the member server that instead of using it's Kerberos AD credentials,
it is falling back to using an NTLM null session. It appears that every
computer that attempts to connect to it (including the domain
controllers) is having this problem. This is not an isolated incident,
I have seen other member servers exhibit the same problem on our AD. The
problem developed over the past few months, but I hadn't noticed it
until recently (i.e. it used to work properly). Has anyone experienced
anything like this, or have any ideas as to why this could be happening?

Thanks,
Dennis Tighe
 
Load. I've seen where DC's strained under heavy load not get the Kerberos
response back to the member server which cause the member server to
basically go "ok, he's not talking Kerberos to me so let me try NTLM
instead". So ntlm works because it is a simpler protocol and the packets
are smaller therefore they go through.
 
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