Jaroslaw Grzabel wrote:
Hi,
Sorry I didn't include any information about version. My postfix version is
2.3.3 installed from yum (Centos 5).
Yeah, I read about stress mode and it looks really good. Anyway I would
rather want to stop reciving connection from postfix than hang the whole
server.
The problem is, Noel advised me to increase default_process_limit but I've
already done it and later postfix hanged with the same message as below. I
think the parameter default_destination_recipient_limit is responsible for
that.
Please don't top-post.
No, that default_destination_recipient_limit is unrelated;
it's only used when sending mail.
You need to keep increasing your default_process_limit until
it's greater than the number of connections being directed at
your server. Postfix on modern hardware will run fine with
far more than the default number of processes.
So what are all these connections? Legit mail? Spam flood?
Hanging Zombies? Klingons? That's important to know before
you decide what to do next.
If you're under attack from spambots/zombies that are holding
connections open for too long, you can add
# main.cf
smtpd_timeout = 60s
which is not RFC compliant, but seems to be safe for general
use. Also see the other suggestions in the STRESS_README. In
particular, the section
http://www.postfix.org/STRESS_README.html#legacy
discusses settings that will work with your version of postfix.
But if your server is simply busy with lots of legit
connections, this won't help. In that case you need to
provision for the load.
-- Noel Jones
