Question : Sharepoint 3.0 permissions resetting

We're experiencing some weird problems with the permissions on our Sharepoint.

We have set the permissions on the top-level site (parent - http://companyweb) and we also have about 5 different subsites inheriting the permissions from the parent site. Inside the 5 subsites, there are different lists and documents.

A while back we've set the permissions on some of the lists to inherit from the parent site, but then we changed our mind and set unique permissions to them. For some reason, after a few days its resets back to inheriting its permissions from the parent site.

Question(s):
1. When you set the permission on a subsite to inherit its permissions from the parent site, does it propagate down to all the lists/galleries/documents inside it?
2. Is there a reason why the unique permissions that are set to some of the lists/documents are reset back to inherit its permissions from the parent site?
3. How can #2 be fixed or prevented?

**We do not use Sharepoint Groups as there are a lot of different permissions that we set for each lists,subsites,etc.. and its a PITA in making up names and maintaining them**

any help would be appreciated.

thanks!

Answer : Sharepoint 3.0 permissions resetting

This is how it works.

Inheritance:

Site A - User 1,2,3
     Site AA - Reference to security of A
         Site AAA - Reference to security of AA

If now, in site AA you decide to break inheritance you will have

Site A - User 1,2,3
     Site AA - User 1,2,3
         Site AAA - Reference to security of AA
(user 1,2,3 already have acces to Site AA so they are stored on the level of Site AA now)

So if you add a user 4 to Site AA the situation will be

Site A - User 1,2,3
     Site AA - User 1,2,3,4
         Site AAA - Reference to security of AA

and user 4 will appear both in AA and AAA

now, if you expand this with two more sites, one with and one without inheritance

Site A - User 1,2,3
     Site AA - User 1,2,3,4
         Site AAA - Reference to security of AA
             Site AAAA - User 4,5,6,7
             Site BBBB - Reference to security AAA

if you then put Site AA back at Inheritance, you will get

Site A - User 1,2,3
     Site AA - Reference to security of A
         Site AAA - Reference to security of AA
             Site AAAA - User 4,5,6,7
             Site BBBB - Reference to security AAA

In that case, for subsite BBBB the rights will change from 1,2,3,4 to 1,2,3
For subsite AAAA nothing will change, as it broke it's inheritance with its parent

I hope this makes everything clear. Personally, I advise not to use breaking inheritance too often as you can image adding one user to all those sites that have broken inheritance is a PITA.

It is not normal that the security changes overnight unless you recovered from a backup (or someone changed it back)