> From: Scott Undercofler via mailop Sent: February 1, 2024 17:04
> >
> > The issue you´re seeing is directly related to SMTP smuggling which
> > was discussed on list ad nauseam about a month ago.
>
> I did see those but they did not appear to relate to anything we are
> doing so I did not read them in detail. I will now go back to these in
> the list archives.
>
> > The servers at shaw are configured to reject non-RFC bare linefeeds.
>
> Silly me I was looking for bare CRs as the error message advised. I will
> now go back and review the code for bare LFs. I am also having the code
> reviewed by someone else.
Feel free to contact me off-list so I can set up a special test
address for you -- we're rejecting incorrectly formatted messages as
well, and won't mind you running tests against our systems in the
hopes that it helps you in your work on resolving this problem.
> > Can you elaborate on why you´re sending them as they are not allowed.
>
> If we are sending them we are not doing so intentionally. The code in
> question was reviewed and updated for CR/LF pairing many years ago and
> has been running fine until now.
Yes. That's likely the case for a lot of people since this SMTP
Smuggling issue got into the spotlight in mid- to late-December 2023.
> We are a little suspicious that the issue is only occurring with mail
> sent to shaw.ca email addresses. Shaw was recently acquired by Rogers
> and they are in the process of merging Shaw operations into Rogers so
> it is not inconceivable that problems might occur during this merger.
> We are trying to reach techs at Shaw but it is not easy.
This is not a Shaw-to-Rogers migration issue. There's a patch that
was released for various mail servers in late December 2023 to
prevent SMTP Smuggling from working, which is isn't as widely
deployed as it should be -- my guess is that Shaw/Rogers have
recently implemented this patch in the normal course of installing
security updates to their systems.
> In the interim, we will continue to review our code and operations to
> see if it is a problem at our end.
>
> Thank you very much for your suggestions.
>
> Regards, Hugh
>
> --
> Hugh E Cruickshank, Forward Software, www.forward-software.com
>
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Inter-Corporate Computer & Network Services, Inc.
Vancouver, Beautiful British Columbia, Canada
https://www.inter-corporate.com/
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