[Discuss] [POSSIBLE SPAM] Spam

[brendan]

On 16-05-14 11:42 AM, John Blomfield wrote:
> Thanks Brendan. However, I don't seem to have anything labeled rcpt in
> the header nor can I see any entry to jabfield at shaw.ca.

that probably just means your mail server doesn't add the return-path
header when it delivers mail to you.

once in a blue moon a mail provider will have some sort of config
problem where mail gets delivered to the wrong recipient, but that's
exceedingly rare.

BCC is a good practical example of how the message headers don't line up
with message delivery - email addresses BCC'd don't end up in the
headers, but are present in the mail to: section of the message envelope.



> 
> John
> 
> On 05/14/2016 11:08 AM, brendan wrote:
>> the To: field in an email message is not actually used to deliver the
>> message - it's just an informational field for the recipient and may not
>> be accurate if the sender is lazy.
>>
>> delivery is actually controlled by the smtp envelope rcpt to, which is
>> often added as the Delivered-To: header inside a message by the
>> receiving smtp server.
>>
>> an smtp transaction would look something like:
>>
>> < 220 mail.blah.blah.com SMTP
>>> helo i.am.a.pony
>> < 250 mail.blah.blah.blah
>>> mail from:<brendan at ming.org>
>> < 250 2.1.0 Ok
>>> rcpt to:<b at b.com>
>> < 250 2.1.5 Ok
>>> data
>> < 354 End data with <CR><LF>.<CR><LF>
>> < Subject: Blah blah blah
>> < From: <lies at ming.org>
>> < To: <nobody at ming.org>
>> <
>> < blah blah blah
>> < .
>>> 250 Ok Queued as fang38_fb8422e34747
>> the rcpt to command determines who the mail is going to, mail from is
>> who is was sent from. the From and To in the data/headers section are
>> irrelevant.
>>
>> however, spam filters will try and take a discrepancy between the
>> envelope mail to and message header To and score messages that don't
>> match as more likely to be spam.
>>
>> On 16-05-14 09:50 AM, Deryk Barker (Honorary Colleague) wrote:
>>> You are on a Bcc list?
>>>
>>> -------
>>> Deryk Barker, Faculty Emeritus
>>> Computer Science Department
>>> Camosun College, Victoria BC
>>>
>>> ________________________________________
>>> From: Discuss [discuss-bounces at vlug.org] on behalf of John Blomfield
>>> [jabfield at shaw.ca]
>>> Sent: Saturday, May 14, 2016 9:19 AM
>>> To: discuss at vlug.org
>>> Subject: [POSSIBLE SPAM]  [Discuss] Spam
>>>
>>> I have recently been receiving spam emails which is not unusual but
>>> these emails are not addressed to my email address but to someone
>>> else's. There does not seem to be any link to my email address in the
>>> header. How is it possible for these emails to end up in my inbox?
>>>
>>> Any ideas anyone?
>>>
>>> John
>>>
>>> -- 
>>> John Blomfield
>>> Delivered by Thunderbird Email on Linux OpenSuse-KDE4
>>>
>>>
>>>
>>>
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> 
>