dovecot - Jun 2021 - good options for Multiple users on a common email account

Hi,

i ve a mail server to manage with some email accounts but with multiples users
(+50) using a common email.
it indicates sometimes that it can't connect cause too many connections.

what are the good options to allow a lot of users for a specific account ?

i modifyied these options :
auth_worker_max_count = 60
mail_max_userip_connections = 60

is it sufficient ?

dovecot -n :

auth_worker_max_count = 60
mail_location = maildir:/home/%u/Maildir
namespace inbox {
  inbox = yes
  location = 
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix = 
}
passdb {
  driver = pam
}
protocols = " imap"
service imap-login {
  inet_listener imaps {
    port = 993
    ssl = yes
  }
}
ssl_cert = </etc/ssl/certs/dovecot.pem
ssl_key =  # hidden, use -P to show it
userdb {
  driver = passwd
}
protocol imap {
  mail_max_userip_connections = 60
}


Regards,


-- 
patg

>>>>> "Pat" == Pat G <patgsiosisr at gmail.com>
writes:

Pat> i ve a mail server to manage with some email accounts but with
Pat> multiples users (+50) using a common email.  it indicates
Pat> sometimes that it can't connect cause too many connections.

Can you post some log messages from around when this happens?  It
should be easy enough to generate loadby running abunch of fetchmail
processes or other imap CLI tools against those shared accounts. 

Pat> what are the good options to allow a lot of users for a specific
Pat> account ?

I'm honestly not sure, but it shouldn't care whether it's one
account
logged in multiple time, or a whole bunch of accounts all accessing
their own mailboxes.  

Pat> i modifyied these options :
Pat> auth_worker_max_count = 60
Pat> mail_max_userip_connections = 60

Pat> is it sufficient ?

Pat> dovecot -n :

Pat> auth_worker_max_count = 60
Pat> mail_location = maildir:/home/%u/Maildir
Pat> namespace inbox {
Pat>   inbox = yes
Pat>   location = 
Pat>   mailbox Drafts {
Pat>     special_use = \Drafts
Pat>   }
Pat>   mailbox Junk {
Pat>     special_use = \Junk
Pat>   }
Pat>   mailbox Sent {
Pat>     special_use = \Sent
Pat>   }
Pat>   mailbox "Sent Messages" {
Pat>     special_use = \Sent
Pat>   }
Pat>   mailbox Trash {
Pat>     special_use = \Trash
Pat>   }
Pat>   prefix = 
Pat> }
Pat> passdb {
Pat>   driver = pam
Pat> }
Pat> protocols = " imap"
Pat> service imap-login {
Pat>   inet_listener imaps {
Pat>     port = 993
Pat>     ssl = yes
Pat>   }
Pat> }
Pat> ssl_cert = </etc/ssl/certs/dovecot.pem
Pat> ssl_key =  # hidden, use -P to show it
Pat> userdb {
Pat>   driver = passwd
Pat> }
Pat> protocol imap {
Pat>   mail_max_userip_connections = 60
Pat> }

I would just bump those two numbers up and load test with an IMAP
client you can script out.  Shouldn't be too hard to do.

John

On Wed, 23 Jun 2021, Pat G wrote:
> i ve a mail server to manage with some email accounts but with multiples
users (+50) using a common email.
> it indicates sometimes that it can't connect cause too many
connections.
>
> what are the good options to allow a lot of users for a specific account ?
>
> i modifyied these options :
> auth_worker_max_count = 60
> mail_max_userip_connections = 60
>
> is it sufficient ?
Probably not, but it depends on the mail client they are using.
Some mail clients chew up 3 or 5 concurrent connections per session.
MacOSX Mail.app will consume all the connections while doing global
pattern searching (i.e. if you allow 200, it will open up 200 connections
at a time before closing them).

If your users use POP3, then the limits have a good chance of working.

If too many concurrent connections becomes a problem, maybe you can
use mailbox sharing rather than single account access.

Joseph Tam <jtam.home at gmail.com>