Strange error with MSMilter

Mark Sapiro mark at
Tue Nov 20 19:09:30 UTC 2018

I am running MailScanner at rev 941ac5ada. My milter config is

Incoming Queue Dir = /var/spool/MailScanner/milterin
Outgoing Queue Dir = /var/spool/MailScanner/milterout
MTA = msmail
MSMail Queue Type = short
Milter Scanner = yes
Milter Dispatcher = postfork

I have a strange issue that I have seen twice. The issue is two emails
arrive at the essentially the same time. One is delivered normally, but
the other is missing what at time of receipt is probably just the first
line of the header. In the second case, the remaining header starts with
a continuation line so it appears the message has no headers and the MTA
later adds minimal headers.

The two cases I've seen have almost nothing in common other than the
fact that two separate emails arrive from the same server in immediate
succession, but in separate SMTP sessions, and have similar content, but
the sending server, the recipients and the message content were
different between the two instances.

There are other cases where the conditions are similar and the issue
doesn't occur.

The following is from the second instance. The messages were a notice
from to mark at and webmaster at The message
to mark was received normally, but the message to webmaster was missing
the header line.

The other interesting thing in the Postfix log is it looks like the
message to webmaster was the second of two transactions in the same SMTP
session and further, the MailScanner child was restarted between the two
transactions. It is this second message to webmaster that was missing a
line, so it is quite possible that the issue occurs to the second of two
transactions in the same SMTP session and has nothing to do with a
similar message arriving separately at the same time.

The Postfix log for the period is <>.

The garbled message to webmaster is

The message to mark is <>.

Mark Sapiro <mark at>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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