[Dovecot] How to limit max number of connections for ip address

Timo Sirainen tss at iki.fi
Sat Feb 25 02:27:22 EET 2012

On 24.2.2012, at 17.07, Wilberth Perez wrote:

> My question was because constantly we received brute force attack from
> some of ip address which uses pop3 service to affect dovecot's login
> proccess.
> For example:
> dovecot: Error: pipe() failed: Too many open files
> dovecot: Error: Temporary failure in creating login processes, slowing
> down for now

This is your main problem. Increase ulimit -n so Dovecot won't stop creating login processes (or alternatively decrease the max number of login processes). Newer Dovecot versions warn at startup if the fd limit is too low.

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