sendmail -- restricting remote auth/login to specific users
I'm after some sendmail help.
I've configured my sendmail server to allow encrypted (starttls), auth/logins so that I'm able to send email from my mobile phone. However I'm looking to lock it down further (as a number of users use this server), can anyone tell me how I limit sendmail to only allow certain uids or usernames to login/auth rather than all valid users (which it seems to)?
I've tried hunting for ages but 'sendmail auth login' searches tend to reveal too many hits and I can't find anything related to this query :(
Thanks in advance for any assistance,