In your second bounce message example, at the end of the DATA
command, the bounce message shows that server and client are out
of step.
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<s.dewa...@example.com>: host 129.50.20.41[129.50.20.41]
said:* 552 5.2.2 r.beer...@example.com Quota Exceeded (in
reply to end of DATA command)
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<s.kers...@example.com>: host 129.50.20.41[129.50.20.41] said:
552 5.2.2 s.dewa...@example.com Quota Exceeded (in reply to
end of DATA command)
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I replaced the domain with "example".
This shows two things:
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1) Postfix uses the LMTP protocol to deliver mail to the remote
server at 129.50.20.41. Unlike SMTP this has one "end of data"
response per recipient.
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2) The responses reveal that the remote LMTP server at 129.50.20.41
is out of step with the Postfix LMTP client (replies for one
recipient are sent in place of another recipient). The Postfix
LMTP client code is 10+ years old. I therefore suspect bugs in
the remote remote LMTP server. You can demonstrate this with a
network sniffer (http://www.postfix.org/DEBUG_README.html#sniffer,
replace 25 with the port number that you use for LMTP)
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You may be able to prevent the "out of step" problem by turning off
PIPELINING support.
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/etc/postfix/main.cf:
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# Work around for buggy LMTP servers that mis-implement RFC 2920.
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lmtp_discard_lhlo_keywords = pipelining
Wietse
