[Dovecot] Master user creds for proxy stored statically/locally?

[Edward Carraro]

I have successfully set up the master user on the destination server
(2.0.11) and tests have worked. now I'm working on the proxy
Before I had the proxy just forward everything to the backend and had the
destination server do the authentication.

My authentication is done via LDAP but not really sure how to append the
master user and password to the users credentials after authentication is
done.
id rather not have the master user/pass in each users ldap entry and
returned after doing a lookup or add a destuser field for each user...
basically i prefer not having to add any new attributes to LDAP

Can the information be stored locally in a file on the proxy? do i just make
the same master user file that I have on the backend?

Thanks!