Hi Jeff,
What version of qmail are you running?
Eric
On 8/29/2022 9:32 AM, Eric Broch wrote:
Jeff,
Are you using spamdyke?
How spamdyke works: When a message is not blocked
spamdyke works by acting as a middleman between qmail and the network
(in Unix terms, it's a pipe). When no spamdyke filters are triggered
and a message is delivered normally, spamdyke silently passes data in
both directions. As the SMTP conversation takes place, spamdyke
collects a few pieces of data (e.g. the sender and recipient
addresses) so they can be logged.
spamdyke does modify the incoming message in one way. The SMTP
protocol requires the remote sender to end every line with a two
character terminator -- a carriage return and a line feed. Unlike most
other mail servers, qmail chooses to strictly enforce this
requirement. If a remote sender uses only a line feed to end a line (a
typical and easy mistake to make), qmail will reject the message:
|451 See http://pobox.com/~djb/docs/smtplf.html.|
Because qmail's strict enforcement of the protocol tends to cause more
problems than it solves, spamdyke silently helps mail clients avoid
this error by inserting a carriage return before any bare line feed
characters it sees. This doesn't affect the messages, it only allows
poorly-written mail clients to send email.
On 8/29/2022 8:20 AM, Jeff Koch wrote:
I do have to say that after running qmail toasters for over 20 years
with over a few thousand users this is the first time I've heard of
this issue. I should be getting complaints up the wazoo. Jeff
On 8/29/2022 10:13 AM, Eric Broch wrote:
Tonix,
In your opinion, could this be fixed with a patch to the 'blast'
function in qmail-smtpd to allow bare line feeds or would there need
to be 'chunking' and 'bdat' calls added to smtp commands as well?
Eric
On 8/29/2022 7:16 AM, Tonix wrote:
Not only this (local) sender. Also other SMTP server which relay
messages with same problem, or emails generated by application
programs or network facilities which send simple alert emails not
caring too much about CR LF.
Il 29/08/2022 14:56, Jeff Koch ha scritto:
Hi Tonino:
Does this mean that all of the emails this sender sends through
her O365 server would be rejected ?
Jeff
On 8/29/2022 6:55 AM, Tonix wrote:
More exactly those messages will be rejected by remote O365
receiver servers whose admins will have enabled the
SMTPSEND.BareLinefeedsAreIllegal flag.
Tonino
Il 28/08/2022 22:20, Jeff Koch ha scritto:
Thanks Tonix - so the result is that messages from email clients
(like Outlook) that add multiple bare line feeds in their
messages and use O365 will now get rejected by the qmail
toaster. How nice of Microsoft.
Jeff
On 8/28/2022 2:27 PM, to...@interazioni.it wrote:
This document explains the problem:
https://docs.microsoft.com/en-us/exchange/mail-flow-best-practices/non-delivery-reports-in-exchange-online/fix-error-code-550-5-6-11-in-exchange-online
I will omit my thought on remote admins.
A very simple rule in communication is: be strict when sending,
be tolerant when receiving.
Regards,
Tonino
Il 28 agosto 2022 19:24:13 CEST, Jeff Koch
<jeffk...@intersessions.com> ha scritto:
>Further information:
>
>The sender also got the following message from his exchange
mailserver when trying to send to our mailserver:
>
>Your message contains invalid characters (bare line feed
characters) which the email servers at ......com don't support
>
>Jeff
>
>
>On 8/28/2022 12:45 PM, Jeff Koch wrote:
>>
>> Never heard of this before but an email sender to our
mailserver got the following error message:
>>
>> 550 5.6.11 SMTPSEND.BareLinefeedsAreIllegal; message
contains bare linefeeds, which cannot be sent via DATA and
receiving system does not support BDAT
>>
>> Does anyone know whether the qmail toaster supports the SMTP
protocol BDAT command ?
>>
>> Thanks,
>>
>> Jeff
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