Hello again... I have not been here for a while. :-)

> 1) Security = User
> used if 1 pc is linux-box acting as server
> multiple windows workstations loging to this and accessing shares.

Yeah... Acts like a windows NT / 2K / XP client. - Use this if you can.

> 2) Security = Share
> used when every share needs to be authenticated using the samba
> server.

Do not use this. - It does not work very well and is for compatability with
Wfw and OS/2.

> 3) Security = Server
> used when multiple linux-boxes acting as servers, but, one is acting
> as samba pdc server.
> this linux samba pdc server has security = user
> other linux samba servers have security = server and specifying the
> name/ip of samba pdc server.
> other windows workstations, if would require to access the shares of
> these linux boxes can now do so.

Do not use this. - It is a hack and has many flaws. - See Samba3.0 docs.

> 4) Security = Domain
> used primarily with winbind where password replication is avoided.
> a windows pdc exists, and users/windows-workstations requiring to
> access shares from a linux box/boxes would be able to do so, since the
> passwords would be replicated in winbind, on linux-box.

Use this when servers are a member of a domain. - Domain PDC can be windows
or samba.