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Synchronization between c# app and Active directory

Question:

I'm developing an application that manages information about users and save the data in a SQL Server. I would like to 'somehow' connect this application with our Active Directory, so all the changes this app will make will be reflected in the Active Directory too (if we add a new user in the app, it will be added also in the Active Directory)

Is it possible? if so, which are my options?

Thanks in advance

Answer1:

Don't do it. Let AD be the authoritative copy of your user base, and let the users <em>always</em> be created in AD first and then propagate to SQL. By letting users be added through a different path (SQL first) you open a huge can of worms with regard to security. If a user is defined in SQL but not in AD, what exactly is taht user? How can he log in? To what groups does he belong? IS he allowed access or not to this resource or that resource? How about cases when an user is added in AD <em>and</em> in SQL with different characteristics and then you need to reconcile.

Modify your application do <em>always</em> create the user in AD, in conformance with the AD policies and security requirements (password complexity being the most trivial example). Then let AD synchronize with SQL.

Answer2:

The way I chose to solve this problem was to add an event that was triggered when I saved my user object. The listener on this event would then send an update to Active Directory. In my case I was doing a one way sync to Active Directory and it was also a best effort attempt, meaning if it failed I was fine with it. If you need to do some more reliability around it you will want to wrap your SQL updates inside of a transaction and only commit after active directory is updated.

If you need a two way sync with Active Directory you will need to look at doing some sort of a background synchronization with Active Directory where you iterate over your users and check for updates in AD.

Answer3:

If you are doing a one-way sync to AD, I agree with Aaron that you should simply have a Trigger in SQL server. Note that this solution may suffer from some problems, like the user accounts already created, user name or password doesn't meet the AD complexity rule. You need to then find some ways to log the error. You may also need a tool to do initial provisioning of your database accounts.

If you want to do two-way sync, I suggest you to read up <a href="http://msdn.microsoft.com/en-us/library/ms677974%28v=VS.85%29.aspx" rel="nofollow">DirSync</a>. You probably need to write a NT service to do it. I hope you don't store password in your database. I highly suggest you to use Windows authentication. If you do need to sync up the password, you may need to write your own passwordsync and install it in all the domain controllers in your machine.

If you are developing a solution for enterprise, you should look up the existing meta-directory solution products from Microsoft, <a href="http://technet.microsoft.com/en-us/library/cc720621%28WS.10%29.aspx" rel="nofollow">MIIS</a>, <a href="http://www.microsoft.com/windowsserver/ilm2007/default.mspx" rel="nofollow">ILM</a>, <a href="http://www.microsoft.com/forefront/identitymanager/en/us/default.aspx" rel="nofollow">FIM</a>.

They are all the same thing except with the names different. Many enterprise has adopted this as their meta directory solution. You just need to write up an extension to leverage on its provided infrastructures to do the identity synchronization.

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