Hello Ricardo,
Thank you for your message.
Is there a way to import all host from AD to the General Address book?
Yes, you can bulk-add AD records to the General Address book by right-clicking on a computer in an active directory folder in the Viewer and selecting
Add all computers as records in the drop-down menu:

Also, is there a way to keep Address Books sync between agents with out installing the RU server?
It depends on how many users are going to work with the software. For example, if you are the only user who uses the software on a few machines, then you can get the address book updated automatically through a shared resource, such as a Dropbox or OneDrive folder. Here's a guide on
sharing address book via Dropbox.
However, if there are multiple users, a conflict may occur in which case it would be best to use a more
advanced address book synchronization available in our self-hosted server.
Hope that helps.