We are using Windows 2003 AD with NTLM v1 disabled. NTLM V2 is the enalbed prototcol for authentication. VPN concentrator had been configured to authenticate to the AD and been working fine for the last 1 year. Last week suddenly it stopped authenticating to AD. I had to configure internal user ids to allow VPN connectivity for users. I tried configuring the authentication server as NTLM or Kerberos AD. but none of the configuration help solve the problem.
I would like to resolve the AD authentication problem and reenable AD authentocation for users.