Red Hat Bugzilla – Bug 219762
Sendmail's rate throttling module does not work
Last modified: 2008-08-26 09:32:21 EDT
Description of problem:
We need to implement Sendmail's rate throttling module to automatically
reject hosts which get infected by viruses or spambots. Sendmail does
provide for this in the form of the 'ratecontrol' and 'conncontrol'
modules but they are not working.
Documentation on these modules is available in /usr/share/sendmail-cf/README
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Add lines to /etc/mail/sendmail.mc (after 'FEATURE(access_db):
dnl # Limit machines sending viruses
2. Add lines to /etc/mail/access:
3. Rebuild configuration files and restart sendmail:
m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf
service sendmail restart
We've unfortunately just been blacklisted due to a user's machine being
infected by a spambot which sent out over 16,000 messages over a two hour
The configuration above should automatically limit clients when sending
more than 10 emails within 600 seconds (10 minutes) when the connection
originates from the 192.168.0.0/16 or 10.0.0.0/16 subnets.
*** Bug 219763 has been marked as a duplicate of this bug. ***
What exactly happens with this configuration? Is there a limit at all?
The feature delay_checks is missing in your configuration. Are you sure, that
you were able to generate a working configuration? Trying to apply your changes
results in an error message.
Please have a look at http://www.technoids.org/dossed.html. There you can get
very good descriptions for rate control etc.
This request was evaluated by Red Hat Engineering for inclusion in a Red
Hat Enterprise Linux maintenance release.
As this bug has been in NEEDINFO for an extended period of time we are going
to close this bug due to inactivity. If you would like to persue this
matter feel free to reopen this bug and attach the needed information.
With the goal of minimizing risk of change for deployed systems, and in
response to customer and partner requirements, Red Hat takes a conservative
approach when evaluating enhancements for inclusion in maintenance updates
for currently deployed products. The primary objectives of update releases
are to enable new hardware platform support and to resolve critical
However, Red Hat will further review this request for potential inclusion
in future major releases of Red Hat Enterprise Linux.