Cloud-based scanning

[Glenn Steen]

Well, one problem with doing most any rejections "after the fact" is
that you may become a "spam reflector", apart from the efficiecy
argument (rejections are a LOT cheaper than bounces;-).
ISTR there being a lot of discussion about this about... Ohh... 6?
years ago. There were some trends in how spammers crafted their filth
back then ("joe jobs" etc) that made rejections particularily
attractive. I suppose nothing really has changed on that account.

Cheers!

-- 
-- Glenn

On 3 March 2015 at 15:47, Denis Beauchemin
<Denis.Beauchemin at usherbrooke.ca> wrote:
> James,
>
> Thanks for the info. But if my servers don't send NDRs, people who make a typo in the email address of one of our users won't be notified of the error and will not be able to retry with the correct email address... This is not desirable but on the other hand you are right about address harvesting. And if my servers do send NDRs they could be used to joe-job some poor pal.
>
> I don't really like both avenues...
>
> Thanks.
>
> Denis
>
> -----Message d'origine-----
> De : mailscanner-bounces at lists.mailscanner.info [mailto:mailscanner-bounces at lists.mailscanner.info] De la part de James Nelson
> Envoyé : 3 mars 2015 09:41
> À : MailScanner discussion
> Objet : Re: Cloud-based scanning
>
> Denis,
>
> I also use office 365 for an edge filtering. Mine is synchronized with my internal active directory via the Microsoft Dirsync tool, but aside from the additional load you will place on your internal servers by not offloading directory based blocking at the office 365 level, there's not technically any harm in what you describe, as long as you configure your internal servers not to send NDRs, which in addition to creating additional traffic can be used by spammers for address validation
>
>> On Mar 3, 2015, at 8:22 AM, Denis Beauchemin <Denis.Beauchemin at usherbrooke.ca> wrote:
>>
>> Hello,
>>
>> We are about to move our MX to the cloud in Microsoft 365. The way it would work would be to scan the emails there and then deliver them to our servers.
>>
>> The problem is that we can't for the moment tell MS365 which email addresses are valid and which are not (the data is in an LDAP server that is not synchronized with our AD). Thus MS365 will be forwarding all harmless emails to our internal servers who will reject invalid email addresses.
>>
>> I seem to remember this is really not a good idea but I can't remember why. Can someone shed some light on this please?
>>
>> Thanks.
>>
>> Denis
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-- 
-- Glenn
email: glenn < dot > steen < at > gmail < dot > com
work: glenn < dot > steen < at > ap1 < dot > se