|
FastMail Forum All posts relating to FastMail.FM should go here: suggestions, comments, requests for help, complaints, technical issues etc. |
|
Thread Tools |
9 Apr 2018, 01:53 AM | #1 |
Member
Join Date: Mar 2018
Posts: 53
|
Sender Policy Framework / 3rd party domains / and Sieve
The scenario is this ~ This company (company A) has it recorded in their Sender Policy Framework that another company (company B) with a different domain can send emails on their behalf.
The third party company (company B) sends an email to you from Company A's email address. Can sieve 'see' that the email actually comes from Company B? |
9 Apr 2018, 02:52 AM | #2 |
The "e" in e-mail
Join Date: May 2003
Location: mostly in Thailand
Posts: 3,095
|
Your question can be restated as "can you tell from the email headers that the email originated from company B's SMTP server?"
The answer is almost certainly yes, but has nothing really to do with domain names. Visually examining the full headers from a sample email is the best way of figuring out appropriate sieve tests. |
9 Apr 2018, 03:02 AM | #3 | |
Member
Join Date: Mar 2018
Posts: 53
|
Quote:
|
|
9 Apr 2018, 04:00 AM | #4 | |
Cornerstone of the Community
Join Date: Dec 2005
Location: Kars, NB, Canada
Posts: 702
|
Quote:
However, not all email receivers do this, so the only real way to check it would be to examine a few of the messages sent that way, as BritTim suggested. |
|
9 Apr 2018, 04:02 AM | #5 |
Cornerstone of the Community
Join Date: Dec 2005
Location: Kars, NB, Canada
Posts: 702
|
And even if the domain for company B is not explicitly listed in the "Received:" headers, a person could do a reverse lookup manually on the earliest IP addresses and potentially find it out.
|
9 Apr 2018, 07:39 AM | #6 |
The "e" in e-mail
Join Date: May 2003
Location: mostly in Thailand
Posts: 3,095
|
Consider what you would see if Company B was using FastMail to host its domain companyb.com. When an email is sent by a Company B employee from john.smith@companya.com, the message will appear to be sent using smtp.fastmail.com. or similar. The email headers may provide other clues about the sender (especially if they are not using the FastMail web client) but you need to examine the full headers to determine this. Usually, a genuine email will need to provide a reply-to address. That can provide a good clue as to the real sender. Of course, if it is a phishing email, most of the headers might be complete nonsense.
|
9 Apr 2018, 02:25 PM | #7 |
Member
Join Date: Mar 2018
Posts: 53
|
I appreciate the help I really do but this is drifting way off
Reverse lookups, spoofing or phishing isn't relevant here. Please could we go back to the specific example in the original question "The scenario is this ~ This company (company A) has it recorded in their Sender Policy Framework that another company (company B) with a different domain can send emails on their behalf. The third party company (company B) sends an email to you from Company A's email address. Can sieve 'see' that the email actually comes from Company B?" 1. Yes 2. No 3. Maybe/Sometimes |
9 Apr 2018, 04:19 PM | #8 | |
The "e" in e-mail
Join Date: May 2003
Location: mostly in Thailand
Posts: 3,095
|
Quote:
|
|
9 Apr 2018, 05:14 PM | #9 | |
Member
Join Date: Mar 2018
Posts: 53
|
Quote:
"If you choose to use your own domain for the sender email, ReviewersRUs will send out the invitation on behalf of your email address. In order to ensure the invitation will be delivered successfully, you need to add the phrase include:reviewersRUsservice.com to your SPF record. This will allow ReviewersRUs to send emails on behalf of your domain. An SPF record acts as a gatekeeper and it shows the recipient's mail server which third party domains are allowed to send emails on behalf of your domain." In this instance can sieve see that it is being sent by reviewersRUs? |
|
9 Apr 2018, 08:12 PM | #10 |
Cornerstone of the Community
Join Date: Dec 2005
Location: Kars, NB, Canada
Posts: 702
|
The answer is #3. You would, as we have said, have to check a sample of emails. If the domain appears in a Received header, sieve can find it.
|
9 Apr 2018, 09:40 PM | #11 | |
Member
Join Date: Mar 2018
Posts: 53
|
Quote:
But thank you |
|
10 Apr 2018, 09:29 AM | #12 |
Cornerstone of the Community
Join Date: Dec 2005
Location: Kars, NB, Canada
Posts: 702
|
I did not realize from your prior posts that you were receiving these yourself. If I had your problem, I would just check the headers of two or three of the undesired messages, and look for mention of the review company's domain, or failing that, a consistent sending IP address or fraction of it or maybe a server name. Sieve should be able to filter those to another folder, spam, or discard. If you need help with the sieve code, post again (I am not an expert but may be able to help, and there are others here who are experts).
|
10 Apr 2018, 02:53 PM | #13 | |
Member
Join Date: Mar 2018
Posts: 53
|
Quote:
Thanks for the offer of help with the sieve code I haven't posted the company name but will post it if it isn't against forum rules. I don't know if knowing that would help. |
|
10 Apr 2018, 03:28 PM | #14 | |
The "e" in e-mail
Join Date: May 2003
Location: mostly in Thailand
Posts: 3,095
|
Quote:
|
|
10 Apr 2018, 10:31 PM | #15 | |
Member
Join Date: Mar 2018
Posts: 53
|
Quote:
Am I allowed to mention the name? It is the biggest review site in the UK (although it is Danish owned). Companies give it our email addressees & pay it to harass us for reviews Its Alexa rank is 948 |
|