I have permit_mynetworks before reject_unauth_pipelining in my
main.cf file.  Despite this, postfix logs an entry about improper
pipelining when a mail client doesn't wait for a response before
sending the next command.

As soon as I upgraded postfix from 2.5.5 to 2.7.1, I started getting
the improper pipelining message in my logs every five minutes, which
resulted in noisy logcheck reports.  The problem client was xymon
monitoring smtp/smtps.

I discussed this on the xymon user list and managed to find a
workaround in the xymon configuration, but it should have been
resolved as soon as I added permit_mynetworks to the postix config.

I won't argue the merits of rejecting unauthorized pipelining, I
completely agree with the practice ... but I should have the option
of allowing it if I have a broken program that I have to use.

[Yes, it's been 14 years...]
Is it still a problem today with current postfix versions?

I did't try 2.7.1.  But with current 3.9 I can't reproduce this.
When I've permit_mynetworks before reject_unauth_pipelining, I
can dump whole client-side smtp conversation to smtp port at once.
But when I place reject_unauth_pipelining before permit_mynetworks,
postfix correctly detects and rejects the wrong pipelining.

Thanks,

/mjt