[Dovecot] Dovecot Virtual Users with Sendmail

[Andrzej A. Filip]

On 01/01/2013 06:40 PM, DormitionSkete at hotmail.com wrote:
> On Jan 1, 2013, at 10:31 AM, Andrzej A. Filip wrote:
>
>> On 12/31/2012 04:19 AM, DormitionSkete at hotmail.com wrote:
>>> [...]
>> 1) Do you use virtual users with or without domain part?
>> [virtual-user or virtual-user at exaple.net ]
>
> Without.
>
> virtual-user
>
>
>> 2) How many entries do you have in paswdb/userdb files?
>> [<100,<1000,....]
> <100
>
> Around 10.
>
>
>> 3) Is SMTP AUTH crucial for virtual users?
>>
> No.  I'd like it, but it's not crucial.
>
> We don't have it now for anyone.  The only way we access our email outside the monastery is through SquirrelMail.  I was hoping to add that with this server upgrade.  It'd be nice to open our email access up more, but we can live without it if we have to.    
Based on the above replies I would suggest first modified version of the
recipe below. There are many other ways but it seems to best fit your
case with simple and stable changes to sendmail.mc/sendmail.cf.
  http://anfi.homeunix.org/sendmail/localNalias.html

1) In *.mc file add
LOCAL_CONFIG
# declare DOVECOT "magic word"
CPDOVECOT

2) Deliver messages to *@DOVECOT using dovecot mailer [requires
FEATURE(`mailertable')].
mailertable:
DOVECOT dovecot:localhost

3) Do not accept messages to *@DOVECOT via SMTP [requires
FEATURE(`access_db') and FEATURE(`blacklist_recipients')] access:
to:DOVECOT REJECT

4) create aliases for virtualusers (one alias per one virtual user)
aliases:
virtualuser1: virtualuser1 at DOVECOT
virtualuser2: virtualuser2 at DOVECOT

Comments about "narrowing" questions:
1) case with domain part is usually more complex
2) sendmail may be configured to check recipient existence in dovecot's
userdb/paswdb files but it would use method I would not recommend for
bigger userdb/passwd files
3) sendmail supports cyrus-sasl, sendmail does not support dovecot-sasl