dovecot - Mar 2017 - Dovecot 2.2.27 proxy - enforcing per client IP connection limits

Adi Pircalabu writes:
> For us it is, we're periodically getting hammered by iOS devices that
> try to open 300+ simultaneous IMAP connections for a single user from
> the same IP, while the average hovers usually below 50 for the busier
> mailboxes with many folders.
Oh yeah, I've seen this.  I think this happens when someone does a global
pattern search, which causes the client to launch IMAP SEARCH commands
on each and every mailbox.

I've wondered whether installing Solr would alleviate this: it wouldn't
directly address the connection limit problem, but perhaps it can
return results fast enough to keep the concurrent connections
count down.

Can anyone with Solr installed confirm/refute this:  does installing
Solr keep iOS clients from roofing the connection count?

Joseph Tam <jtam.home at gmail.com>

> On 16 Mar 2017, at 22.23, Joseph Tam <jtam.home at gmail.com> wrote:
> 
> Can anyone with Solr installed confirm/refute this:  does installing
> Solr keep iOS clients from roofing the connection count?

I doubt it, but since IMAP SEARCH goes all the way down to the backends
mail_max_userip_connections
can be used to limit the number of connections.

Sami