On 9/10/21 12:26 pm, Rob Kampen wrote:
So, after many dozens of hours and sending test emails I have found a
solution (work around) that appears to work okay. It is now different to
the original two MX servers I cloned from, in that the maillog shows a
different cycle of processing, and it now fails a truly unknown mailbox
much later in the process - thus higher workload on my MX. But the key
thing is that it does now do the virtual_alias checks on incoming emails
on port 25 before rejecting.
if your MX is not rejecting messages to invalid recipients right away
but instead bounces the messages later on you become a backscatter
source (See https://www.backscatterer.org/?target=bounces).
your server needs a properly configured list of valid recipients so it
knows right away what recipients to accept and which ones to reject.
No idea why this third MX is behaving differently. It has a dual stack
IP, so I disabled IPv6 access and tried again, but that certainly wasn't
the cause of the difference in processing.
If you can provide the output of the following two commands it would be
very helpful in troubleshooting your problem:
postconf -nf
postconf -Mf
Also of great help would relevant logs for one message that is giving
you issues. These should be in /var/log/maillog and contain a
connection line followed by a number of postfix/smtpd lines, please copy
all the logs for *one* message. Please do not attempt to enable verbose
logging (it only adds in a lot of extra unneeded info that detracts from
finding the real problem) and it is unnecessary to provide log lines
from non-postfix processes.
It should be noted that the two initial MX machines have an extra line
in the maillog that is the second logged step in the process, and goes
something like:
Oct 8 19:00:58 mx policyd-spf[16055]: prepend Received-SPF: None
(mailfrom) identity=mailfrom; client-ip=209.85.210.180;
helo=mail-pf1-f180.google.com; envelope-from=rob@xxxxxxxxxxx;
receiver=<UNKNOWN>
This is likely unrelated to the issue but may point to another issue
having to do with a possibly incorrect policyd setup. We can cross that
bridge after we've fixed the primary issue though (one issue at a time).
After that processing steps are identical.
It's likely that there may be something else subtle in the logs that we
can spot that you are not noticing.
Peter
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