Thread: Spam protection
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Old 27 Jul 2019, 05:58 PM   #32
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Join Date: May 2018
Posts: 296
Originally Posted by SideshowBob View Post
This working well depends on the receiving mail system. Many systems make forwarding unreliable with DMARC. Forwarding can make SpamAssassin less effective unless it's been configured to parse Received headers across each forwarding service. I don't know what the current situation is, but Fastmail has in the past put a lot of effort into making it work.
I've never had a problem no matter what service I've used over the years. But last year (my 1st year with FM) I did get one X-Spam-known-sender set to "no" because "Email failed DMARC policy for domain". From my state tax board no less and then only for acknowledging logging in! It was ending up in my spam folder even though they were in my contacts (which was, at the time, the reason I created a ticket - I wanted contacts in the inbox no matter what). Turns out FM did that because they didn't trust the forwarder. Not sure what the tax board did in that particular message to trigger this in the first place.

After more discussion with FM they said they would look into my forwarding service to see if they were a "trusted forwarder such that mail they forward will not be penalized for DMARC failures". It didn't take much convincing for them to add my service to their whitelist so all is good forwarding from my service (see below) including the case that triggered this problem to begin with.

The problem is that Fastmail may decide to stop bothering, or even implement DMARC rejection, or you might have another reason to leave. At that point you may struggle to find a good replacement.
As I said no problems before I came to FM last year and then only this one occurrence which is now fixed too.

There's also the possibility that the organization providing the portable address discontinues the service, outsources it to Yahoo or replaces it with their own webmail.
The forwarding service (there is no actual mail service) is just a benefit of being a member of a major professional computer organization that's been around for over 70 years. They aren't going away anytime soon. And the reason it didn't take much convincing of FM to whitelist them is because they said they are members of that organization too!

IIWY I'd get a domain and forward it to Fastmail while you phase-out the portable address gradually.
I've been with the organization for so long I am now considered a lifetime member and I've use my email address so long it would probably take the rest of my life to phase it out! If it ain't broke I see no reason to fix it now.

As for my original ticket, I believe that if I have someone in my contacts then I want mail from them in my inbox no matter what! So if X-Spam-known-sender says "no" but still says "in-addressbook" I let those through to my in-box. I'll decide whether those are valid or not. So in the end, with this test in place, for me, it doesn't matter how DMARC affects X-Spam-known-sender (unless "in-addressbook" gets removed or course).

Last edited by xyzzy : 27 Jul 2019 at 06:55 PM.
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