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I have a local server running Active Directory, File Server, App Server, for the local network. I also have a remote hosted server (CentOS 6) which runs a small website, and a Sendmail instance which handles the company's email.

Is there anyway i can synchronize the users/passwords between these two, with the AD taking priority.

If that scenario is not possible, what are some alternatives i can look forward to, but keeping these two operating systems. ( Modifying the email server, using openldap for the email server user/pass management and sync-ing that with the AD, others... ? )

Thank you.

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up vote 3 down vote accepted

AD provides an LDAP directory service, so (my first guess) would be looking at some system to make sendmail/dovecot/imap authenticate against the LDAP user/passwords.

Tools like pam_ldap, and nss_ldap, openldap-client and Sasl could be used for this purpose. Ive not actually implemented this one myself but there are some links which might be a starting point..

In this scenario you would maintain a central list of users and passwords in Active Directory, and authenticate the users SMTP request against the LDAP centrally. I am presuming that you also have Dovecot or Cyrus, or some other IMAP/pop3 server to manage access to the mailboxes? Basically, you have a pam module generate a user directory and mailbox on the sendmail/imap host when the user first logs in and is successfully authenticated against the LDAP/AD server. In this way the uses "pulls" their data, rather than explicitly sync's the accounts to both systems.

You can protect the traffic between SMTP/IMAP and LDAP/AD using a self signed cert if you have to do this on untrusted networks.

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Thank you for your answer. I now have a starting point so i can investigate this issue further. – user76022 May 9 '12 at 11:20

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