I have a server CentOS 5.3 and WHM/cPanel 11.24 installed. In exim log files I noticed these wordings next to most of the emails.
Warning: Sender rate (a number, like 2.4) / 1h
Do you have any idea what it means?
cPanel has a ratelimit option on the exim configuration. Basically it tells you for each ip its send rate. You can configure maximum send rate per ip per hour (after which that ip is temporarilty rejected, i.e. with code 4XX) to reduce the server load.