[Dovecot] "Maintenance instance"

[Michael M. Slusarz]

Quoting Timo Sirainen <tss at iki.fi>:

> On 24.10.2010, at 11.36, Edgar Fuß wrote:
>
>>> and gives any user logging in a canned mail
>>> (e.g. "We're doing maintenance, go away")
>> Wouldn't a client that keeps local copies of all IMAP boxes then  
>> synchronize to that canned state, i.e., delete all locally cached  
>> mails?
>
> I'm pretty sure they will. I'm not aware of any good way to handle  
> this, other than ALERTs.

Isn't this the exact reason to return the UNAVAILABLE response (RFC 5530)?

    UNAVAILABLE
          Temporary failure because a subsystem is down.  For example, an
          IMAP server that uses a Lightweight Directory Access Protocol
          (LDAP) or Radius server for authentication might use this
          response code when the LDAP/Radius server is down.

          C: a LOGIN "fred" "foo"
          S: a NO [UNAVAILABLE] User's backend down for maintenance