You best option would be to create a new membership provider  -  it can be coded to connect with external tables or data - and dynamically create a dnn user on the fly - and handle login and authentication of such.

The active director yprovider works this way, as do the facebook / social networking connect providers found on www.snowcovered.com.

There is no need to modify the core in this case - you create your custom provider - install it as an extension - and change a setting in the site settings to tell dnn to use your new membership provider.

The advantage of doing this is that - you can continue to upgrade dnn with new versions - and in most cases your provider will continue to work - yes there are some rare circumstances where a provider needs to be updated if the api changes - but this again would only mean a change and recompile in your provider = not the core.

Westa

Thanks for information. I'm thinking not changing soruce code.
Instead of changing dnn code, i decide to change my code...

my current situation like this :

we have our own membership form and log in section.

1. For new user, whenever user registered, I will need to synchorinze  two Databases. one is for our member table, and the other is  DNN member table (i believe  that's the aspnet_membership and profile table ).

(* user doesn't need to registered again, when accessing from my site to DoNetNuke module (forum. blog)

   I need specific information which SP used for registering and inserting user.


2.  For existed user, assume that two Data table (our member table and  dnn member table)  has been synchorinized
     when user logs in our site , he/she should access Dnn Module (forum, blog)  without logging in agian.

    To do so, i need to add Dnn login Authentication (like session cookies, session) at same time   when user has logged in successfully in my site
 
     how do i get login Authentication information, so i scripted and put into log in section..


I will appericiate any information

Thanks.