I don't know if rotating addresses is the best solution or not. It's
certainly not practical for small QMT installations.
I think in many (if not all or most) of these cases, the user's password
has been compromised. This is especially likely if it's possible to
configure a client insecurely (plain text password with no TLS/SSL).
I've seen this happen on more than one occasion, on a small domain.
Password sniffing does happen.
First step is to ensure that clients cannot attempt to authenticate with
clear text passwords. This can be enforced with dovecot, but we don't
have a way yet to enforce it on the sending/smtp side. I'm hopeful that
Sam will get this feature built into spamdyke in the near future.
Another good defensive weapon is a script I came across on the spamdyke
list today, and hope to make available in some form with QTP in the
future. It's a script that periodically checks the logs for accounts
which have sent more messages in a given interval than some allowed
limit. When it finds such an account, it changes the password, removes
messages from that account still in the queue, and notifies the
postmaster with an email. I think this is very practical, because
passwords do become compromised on occasion, even with full encryption
(human action). The script is written in python, and will need a little
tweaking for the QMT environment, as it's presently written to scan a
spamdyke log (the author wasn't using the submission port at all). I
think it'd be better to scan the send log if that's feasible. Anywise, I
think this approach is promising.
If anyone has any thoughts on this, please chime in. It's in everyone's
interest to be protecting our public IP addresses so they don't get
blacklisted.
Thanks.
--
-Eric 'shubes'
On 05/21/2012 01:42 PM, fmende...@terra.com wrote:
Hello everyone
I am the owner of a growing hosting enterprise in my country (Perú), and
we are facing big rise on our client number.
As an efect of this we are seeying a rise in mail outbound in our
servers. Even thoug we put limits to hourly sending, having more than 9k
clients, all delivering through the same cluster, it lacks of
efectiveness because each server in cluster uses only one ip for sending
tasks. We are now seeying blocking issues because of the many clents
generated traffic.
We talked to some people at godaddy and hostgator, as we know they use a
cluster system that includes on each server a list of IPs that rotates
in a random fashion, so even with high demand quality service on mail
delivery from client accounts is always achieved.
I would like to ask for some guidance and help to this comunity on how
can we could implement such solution to rotate in a random or other way
the IPs for sending clients mails.
I hope you people can see my situation and can help me with this. We
used to work with exim, but since we changed to QMT it was the best
desition we ever made on this matters. Now we need to push it to a next
level.
Thanks a lot.
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