Message contains invalid header

[Simon Matter]

> Marten Lehmann wrote:
>> Hello,
>>
>> from time to time we are getting this message in our exim logs:
>>
>> LMTP error after end of data: 554 5.6.0 Message contains invalid header
>>
>> I have also experienced this error while I'm syncing emails from an
>> old server to our new cyrus mailserver. I have
>>
>> munge8bit: false
>>
>> in my imapd.conf and reject8bit is set to "false" by default. Which
>> headers is cyrus complaining about? I cannot change this world where
>> clients like Notus Notes are sending invalid emails, but simply
>> refusing these mails is a bad choice. And we also have a lot of emails
>> we received in the old setup and I wouldn't know how to explain to our
>> users, that they cannot access these messages any more.
>>
>> How can I make cyrus less strict?
>>
> If it's mails from the broken Lotus Notes client that's the problem (and
> they're the only ones we saw here), it's caused by a null Message-ID
> header; just have your SMTP server remove those. LMTP will generate a
> new, valid message-id when the message is delivered.
>
> in Exim:
> headers_remove = ${if match{$h_Message-ID:}{\N^\s*$\N} {Message-ID} {} }

and with postfix you can try this in header_checks:

# Remove empty Message-ID headers from broken Notes implementation
/^Message-ID:[[:space:]]*$/ IGNORE

Simon