[Info-vax] What is the correct way to contact VSI?

[Arne Vajhøj]

On 11/26/2019 6:51 PM, Arne Vajhøj wrote:
> On 11/26/2019 8:20 AM, Simon Clubley wrote:
>> On 2019-11-25, Arne Vajhøj <arne at vajhoej.dk> wrote:
>>> On 11/25/2019 1:17 PM, Simon Clubley wrote:
>>>> On 2019-11-25, Phillip Helbig (undress to reply) 
>>>> <helbig at asclothestro.multivax.de> wrote:
>>>>> Probably.  Be happy they didn't drop the SMTP connection, 
>>>>> preventing the
>>>>> email from being delivered at all.
>>>>
>>>> No, dropping the connection with a reject status is _exactly_ what
>>>> should have happened, especially if it was a blacklisting issue,
>>>> so that Mark would have been told immediately his email had not been
>>>> delivered instead of him having to wonder if anyone at VSI was ever
>>>> going to get back to him.
>>>
>>> 30 years ago email may have been directly from sender to
>>> recipient, which mean that SMTP reject works.
>>>
>>> But today email will often go through many SMTP servers
>>> and if the fifth out of eight has a spam filter that
>>> doesn't like the email then sender would not see
>>> the reject.
>>
>> Are you sure about that Arne ?
>>
>> There's a difference between routing email within a large organisation
>> and dropping suspect mail with a SMTP reject while it is being received
>> by the machines listed in the MX records for the receiving domain.
>>
>> If it gets dropped at the MX boundary between the sending and receiving
>> organisations, surely the email sender gets to find out directly because
>> of the SMTP reject.
> 
> Am I sure that emails today usually makes multiple hops: yes.
> 
> Am I sure that intermediate email servers may have a spam filter: yes.
> 
> Do I know what percentage has such a config: no.
> 
> It is over 20 years since I last operated a mail server, so
> I am not current on best practice. But based in my general
> knowledge I would not run the spam filter on the first node
> in the org receiving the email - that should be a passthrough
> with no logic in DMZ.
> 
> But even if it were the first at receiver then there is still
> the possibility that there are multiple servers at the sender
> side.

Just for fun I tried sending an email from my US email to my
DK email and look at the headers.

The path seems to be:

my PC -> my US ISP server -> some filter service I assume my US ISP use 
-> another server from same filter service -> some spam filter service I 
assume used by my DK mail provider -> some server at my DK mail provider 
-> some other server at my DK mail provider

Arne