On Thu, Feb 17, 2011 at 07:41:04AM -0500, Jerry wrote:
> > Scalability. One postscreen process can reject more zombies
> > than 1000+ smtpd processes.
>
> Impressive! I did not realize that it was that efficient.
This is easy, one smtpd(8) process handles one connection, on the other
hand, one postscreen(8) process handles as many connections as the file
descriptor limit imposed on the master(8) process. On modern Postfix
builds that are not constrained by select(2) limitations, this limit
can easily be thousands of file descriptors.
Note that for white-listed IPs postscreen(8) passes the connection
file-descriptor to smtpd(8), so the overhead of postscreen on connections
from already known IPs is negligible.
--
Viktor.
