Hello

Is there a way in Postfix to limit email relays to non-existent users?

For example, if an email has over 25% failures in its email sending
attemps in the last hour, block that email for an hour or so.

When, say, hacked scripts are used by spammers to send mass emails, this
would help limit the amount of damage.

I know recent cPanel versions have this sort of check that will reject
email relaying when a email domain exceeds, for example, more than 25%
relays to non-existent email users.

When that happens, the CPanel server outputs something like:

Domain has exceeded the max defe

Hello

I currently have the following configuration on the main.cf
smtpd_sender_restrictions:

smtpd_sender_restrictions = permit_mynetworks,
reject_non_fqdn_sender,
reject_unknown_sender_domain,
reject_authenticated_sender_login_mismatch,
check_policy_service inet:127.0.0.1:10031,
permit_sasl_authenticated

I have a Policy Server running on port 10031 (Cluebringer) to count
emails sent per domain in order to avoid users from overridi

Hello

I'm currently using Postscreen to reduce the number of botspams handled
by our email server, and it's working good.
Is there any way to reduce the postscreen logging level though?
I feel that the information it logs is great while debugging, but once
the server is in prodution it make the log file work "too much" so to say.

Luis Oliveira
Elaconta

Hello

This has been a nut that i haven't been able to crack for a long time
now and i was wondering how one would solve this problem.
My setup is the following:

a) Multiple domains hosted in a single box
b) Postfix delivers emails to virtual mailboxes (so all the domains run
under the same virtual UID/GID).
c) Users are stored in a MySQL database
d) I'm currently using the Postfix VDA quota patch, but it only limits
quota for a single email.
e) The objective is to limit the quota domain wide.

Hello

We've been having huge problems delivering email to hotmail addresses
(Hotmail is blocking all our emails since yesterday without any
plausible reason). Microsoft's phone support is non-existant and they
don't reply to any of our emails, even those sent from Hotmail
addresses. Filled in their draconian sender information form form
hotmail, no reply whatsoever.

Anyway, since hundreds of mailboxes in our server are unable right to
to send emails to Hotmail, we need to find some alternative.