[Samba] Authenticate pptpd server on a domain controller

[Saúl Sigala]

Hello.

I have two servers:
 -One is a vpn server with pptpd. It has debian sarge 3.1, kernel(2.6.8), pptd(1.2.1-4), ppp(2.4.3-2) and Samba(3.0.14a-3). All the accounts to log on the vpn are on /etc/ppp/chap-secrets file.

 -The other is a pdc with samba(2.2.7) in red hat 8 

I want the accounts in the first server (chap-secrets file) authenticate against the pdc server (/etc/samba/smbpasswd) on the second.

I read that it is possible using winbind, kerberos and pam. I have been making some configurations but I haven't made yet it works.  I want to know what is the best way and how to make.

I have traied these two links.:
1- Replacing a Windows PPTP server with Linux HOWTO http://poptop.sourceforge.net/dox/replacing-windows-pptp-with-linux-howto.phtml

2- Chapter 23. Winbind: Use of Domain Accounts http://us2.samba.org/samba/docs/man/Samba3-HOWTO/winbind.html

but the two show the same error when I try to join the pptpd server on the pdc. All the configurations were made in the pptpd server not on the pdc.

-The fisrt one displays
   Proxy2:/etc/samba# net join -U root
   root's password:
   [2005/07/22 16:02:01, 0] utils/net_ads.c:ads_startup(191)
    ads_connect: Transport endpoint is not connected
   [2005/07/22 16:02:01, 0] rpc_client/cli_netlogon.c:cli_nt_setup_creds(256)
    cli_nt_setup_creds: request challenge failed
   Creation of workstation account failed
   User specified does not have administrator privileges
   Unable to join domain DUCOR.

-The second one displays
  Proxy2:/etc/samba# net rpc join -S servdb1 -U root
  [2005/07/22 16:03:35, 0] rpc_client/cli_netlogon.c:cli_nt_setup_creds(256)
    cli_nt_setup_creds: request challenge failed
  Password: 
  Creation of workstation account failed
  User specified does not have administrator privileges
  Unable to join domain DUCOR.

I would thank if somebody can help me.