Dovecot 2.2.27 proxy - enforcing per client IP connection limits

[Adi Pircalabu]

On 16/03/17 11:03, Timo Sirainen wrote:
> 
> No plans to support enforcing at proxy level. One problem here is that there are no guarantees that the connections even end up in the same proxies, although I guess if your load balancer does IP stickiness that could work well enough.
> 

With or without a load balancer in front of the proxies, it's still very 
manageable. Even without a load balancer, if you have say 
proxy_mail_max_userip_connections=n and m proxies, the maximum number of 
connections that can hit the backend at any time for an user is n*m.
Would this help me to better manage the resources? Think it would.
Is there a business case for the feature? 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.

Thanks,
Adi Pircalabu, System Administrator