And unfortunately, this is why the reliability of the Nissan Pathfinder has become utter shit. I wanted to buy a 2014 model, but the horrific reviews of failing transmissions at 30k miles scared me and many others off. For good reason I might add.

Who cares when your artificially and ridiculously low data cap is exceeded in 5 minutes?

I agree that moving to a VPS would solve the problem. But you got me - I'm stubborn as all hell and refuse to let this beat me. I really want to find a technical solution to keep things the same as they are now.

You guys crack me up. To answer the questions:

1) Absolutely. The first thing I did when I moved to this net block on comcast is have them create my associated pointer records, so reverse DNS is correct.

2) Yes, MX records are correct.

3) I've checked every blacklist using sites like mentioned above. My IP does not exist on a single one.

4) No forwarding.

5) Yes, I monitor my network traffic in various ways - and no, I am not sending spam. If I was, it would be a matter of hours before I would show up on an RBL anyway, which I'm not on.

6) Absolutely. I have paid for a cert that matches my domain. It's not self signed.

I think some others have brought up some things that I'm not doing:

1) DKIM. I've read about this, but I didn't realize a lot of people were using it yet. Sounds like they are and that I'm behind the curve here.

2) DMARC. Same here. I've read about it, but not using it yet.

I'm also using SPF.

Yes, I've monitored traffic. And no, my system has not been compromised.

If you read the actual summary up top, you'll see that I am using business class. And yes, I do have a valid domain associate with it, reverse PTR record and all.

Yes, obviously I have an FQDN. And yes, I have SPF set up - that was mentioned in my original question up top. No, I do not have DKIM or DMARC set up, but based on a lot of feedback today, I most certainly will by tomorrow morning. Thank you for your input.

This has been done for the past 2 years, so I'm good there.

DMARC is definitely at the top of my list to make sure I have set up after reading about it today. Thank you for the input.

What?? That link you posted references users who are sending email AS yahoo email users, via a server that is not Yahoo. That is not all what my question was about. What your link does show is that those major providers all use DMARC, so that's an interesting item that ties all those providers together.

You forgo the last part of that I assume, the 7.

Yes, I have 5 IPs. It's a pain, but yes, I can try one of the others. In regards to the cable modem - it's set up in a manner that the single outgoing IP for my mail server is directly linked to it. So, when I say I ran wireshark on the traffic, I did so for that IP. It is the only machine on the network that uses that IP. The results were well within what I expected for email traffic. Most of the traffic is incoming spam, and the only outgoing messages are being sent by valid users - and not many of them at that.

I've run SPF for years now, and I pass all the associated tests there. I have a valid PTR record that matches my domain. I do not currently use DKIM, but I guess that's my next attempt at fixing this. DMARC also sounds interesting, I have never heard of that before. I will gladly configure DKIM here and then look into DMARC. Thanks for the information.

I'm the guy who asked the question, and spammer I am not. I hate spam more than most people since I run my own mail server, and have for years. Back before spamassassin, my email server was basically unusable, thanks to the fact my personal email address was associated with my whois record. I'm just a poor asshole who signed a 3 year contract with comcast, and 2 years in, my connection became unusable for relaying email.

Yes, I have proper reverse DNS and SPF records. So, I'm good to go there.