Hello, First of all hats off to the people that maintain this website and forum. Big big thank you for what you do. It is highly appreciated. I have a few questions about virtual users/domains if someone enlighten me please? I have studied bunch of O'Reilly books recently (some are still being read now) so as this often happens I have tons of new commands, acronyms and abbreviations in my head and need to tie them up into a small business mail server called WonderfulMail.StampyNetworks.Com (name is not for sale don't ask) for topic's sake. I will put my thoughts alongside questions. Sorry if they sound dumb and please bear with me as it is the my first and by far longest thread. 1. I have noticed that quite a few writeups here feature MySQL as a database for storing (hundreds or thousands) virtual users' passwords and emails as opposed to Postfix map files. Although encrypted passwords and ease of scalability and maintenance are a clear advantage I am somewhat unsure if using MySQL to store 20-50 users is justified? I am in fond of 'keep it simple' rule and running an SQL instance for a few dozens of records does not sound right enough for me. Please note that I do not question the experience of the author of articles, majority of whom were written by guru Falko Timme, but simply want to dig a little bit deeper into reasoning before applying it to my setup. 2. I am pursuing virtual users / virtual domains scheme. As I understand it (please correct me otherwise), virtual users are not system users i.e. they are not created with useradd and are not assigned UID automatically. Taking this into account I wonder where in Postfix files we use them usernames? I read about virtual UID file but all I can see there according to the Postfix documentation is: email...UID and not actual username. Where do we map username with UID? I take it if I use MySQL I don't have to map UIDs? 3. A mail server (to remind: WonderfulMail.StampyNetworks.Com NOT for sale!!) is going to host up to 10 additional virtual mail domains (I am gonna be sooo cool!). Those 10 virtual domains will for sure have common usernames like 'sales' or 'info' (pls note that email@example.com and firstname.lastname@example.org are two separate mailboxes for two different people). I take it MySQL as well as Postfix will not like non-unique usernames? In which case I will follow the convention of naming my users according to domains in which they reside. That is: Bob.Domain1.com is one user whereas Bob.Domain2.com is another. I guess if I were to use Postfix config files I would map emails email@example.com to first Bob and firstname.lastname@example.org to the second. How is that done in MySQL? Or are non-unique (=same) usernames allowed? Basically I guess you get the idea: trivial mail server with 10 virtual domains and identical yet separate users. I don't know which scheme (MySQL or Postfix map files) to follow to get this working right. I need simple (minimal) maintenance as I have only a dozen of domains with handful of users in each. Thank you for your time.