by Lizzy Ralph.
Hi Randy,
Thank you very much for your opinions.
My PHP version is 5.3.10 which shouldn't be an issue for running external database.
I have tried MNet. It works; however, it is not 100% a solution I am looking for.
I want the users in moodle A can log in moodle B, but not the other way around.
Also, moodle public key expires every 28 days. Does it mean I have to update the public key for both moodles every 28 days?