dovecot - Jan 2016 - remote | local blocks in protocol settings

On 19 Jan 2016, at 13:34, Nikolaos Milas <nmilas at noa.gr>
wrote:
> 
> On 15/1/2016 8:02 ??, Nikolaos Milas wrote:
> 
> Having received no reply, I tried using the above info by configuring:
> 
>   protocol imap {
>      imap_client_workarounds = "delay-newmail"
>      mail_plugins = quota imap_quota notify replication
>      mail_max_userip_connections = 30
>      remote 127.0.0.1 {
>        mail_max_userip_connections = 1000
>      }
>   }
> 
> but it didn't work:
> 
>   Fatal: Error in configuration file /etc/dovecot/dovecot.conf line
>   30: remote must not be under protocol
Change it the other way around:

remote 127.0.0.1 {
  protocol imap {
    ...
  }
}
> By the way, the command "doveadm who" shows imap connections by
users, but it does not seem to show webmail connections. Any advice on this?
Webmail probably just quickly opens and closes the connections, so there
aren't any connections that are visible for more than a fraction of a
second.

On 19/1/2016 3:31 ??, Timo Sirainen wrote:
> Change it the other way around:
>
> remote 127.0.0.1 {
>    protocol imap {
>      ...
>    }
> }
Thank you for your advice Timo (on "remote" blocks).

So, the "remote" block should not have any parent (i.e. should not be 
included in any other block)?
> Webmail probably just quickly opens and closes the connections, so there
aren't any connections that are visible for more than a fraction of a
second.
On the real issue: I am trying to identify why (just recently) webmail 
users recently are increasingly facing the error: "ERROR : Connection 
dropped by imap-server".

The docs I've read on webmail (squirrelmail) affirm your indication that 
webmail IMAP connections should be closing quickly, so these should not 
be the cause of the errors.

A few days ago, when I increased the global value of 
"mail_max_userip_connections", I stopped seeing errors "Maximum
number
of connections from user+IP exceeded" in dovecot log. However, the above 
problem continues in webmail.

Using the command "doveadm who" I see relatively few connections, so I
am wondering what may be the cause.

Any ideas will be appreciated!

Thanks,
Nick

>> Webmail probably just quickly opens and closes the connections, so 
>> there aren't any connections that are visible for more than a
fraction
>> of a second.
> 
> On the real issue: I am trying to identify why (just recently) webmail
> users recently are increasingly facing the error: "ERROR : Connection
> dropped by imap-server".
> 
> The docs I've read on webmail (squirrelmail) affirm your indication
> that webmail IMAP connections should be closing quickly, so these
> should not be the cause of the errors.
> 
> A few days ago, when I increased the global value of
> "mail_max_userip_connections", I stopped seeing errors
"Maximum number
> of connections from user+IP exceeded" in dovecot log. However, the
> above problem continues in webmail.
Don't know if that helps but you could try a local imapproxy like 
imapproxy from imappproxy.org this should speed up your webmail and 
reuse connections
> Using the command "doveadm who" I see relatively few connections,
so I
> am wondering what may be the cause.
> 
> Any ideas will be appreciated!
> 
> Thanks,
> Nick
Christian

> On 19 Jan 2016, at 16:04, Nikolaos Milas <nmilas at noa.gr> wrote:
> 
> On 19/1/2016 3:31 ??, Timo Sirainen wrote:
> 
>> Change it the other way around:
>> 
>> remote 127.0.0.1 {
>>   protocol imap {
>>     ...
>>   }
>> }
> 
> Thank you for your advice Timo (on "remote" blocks).
> 
> So, the "remote" block should not have any parent (i.e. should
not be included in any other block)?
I just updated the error messages to be a bit more understandable:
https://github.com/dovecot/core/commit/0df899feada1f406122d7658894c77eeb10225a3

The nesting must be in this order or it'll give an error:

local 127.0.0.1 {
  local_name foo {
    remote 127.0.0.1 {
      protocol imap {
      }
    }
  }
}
>> Webmail probably just quickly opens and closes the connections, so
there aren't any connections that are visible for more than a fraction of a
second.
> 
> On the real issue: I am trying to identify why (just recently) webmail
users recently are increasingly facing the error: "ERROR : Connection
dropped by imap-server".
1) Is there anything in Dovecot's error logs? For example any warnings about
reaching a process limit?

2) If you can't find anything, try to find the matching webmail
connection's disconnection message from Dovecot logs and see what it says
the reason for disconnection was.
> A few days ago, when I increased the global value of
"mail_max_userip_connections", I stopped seeing errors "Maximum
number of connections from user+IP exceeded" in dovecot log. However, the
above problem continues in webmail.
If that is reached, Dovecot logs it as the reason for the disconnection.