It's been two months since I am running a mail server. I worked on a beautiful UI like SendGrid and MailGun for more than six months. I plan to start a transactional email service.
I bought a range and rented another /24 range because I didn't want to have a bad neighbour on the subnet. I even got my own ASN because jerks like UCEProtect often put big ISPs on a blacklist at the ASN level.
Of course, I have got a decent experience with this. I wrote my own SMTP server, email routing, and other things such as bounce and suppression handling. In a sense, everything is fine. RDNS, DKIM, DMARC, and SPF.
I know that IP needs to warm up, so that's where I started. I paid for a few services to help me warm up, and it took me about two months to do so. Okay so far. The email was delivered 100% of the time to Gmail, but not at all to Yahoo and Outlook. The delivery rate to these two companies started to get better around last week, though. Some IP addresses started getting a 100% delivery rate.
Then, I started testing my service on one of my websites. Of course, 100% transactional emails with account confirmation links ONLY. It was working great. Nearly 2,000 emails, 3,000+ opens and about 2,500 clicks daily on an average.
I've also subscribed to Glock Apps and MXToolbox to measure my email deliverability and monitor IPs.
Just today, I received an email with all half of my active IP addresses and sending/tracking domain blacklisted by Spamhaus. They categorize it under "spam domain", but I looked through my server logs (yes, everything is logged) and found no evidence of spam. Only transactional and warmup emails sent. I opened a ticket with Spamhaus and refuse to unblock my IP addresses and domains.
I spent 6 months and $20,000+ working on this, only to be butchered by Spamhaus. I want to kill myself. How can Spamhaus be the police, judge and the executioner?
I'm with you. I hosted my own mail server for about five years before giving up, and it irritates me when folks say it's not that bad.
Even with perfect DKIM and DMARC configurations, spam filter lists would add me silently and repeatedly, and I'd frequently have to go through their processes to remove my domain. Then Google would sometimes start treating me as spam too, or outright deny email delivery, requiring some tweak or another to enable delivery.
It was a constant battle, one in which you don't always know when you're losing since nobody reaches out to tell you when you've been blocked. It was exhausting.
Giving up and moving to Proton was a sad moment. I really wanted to stay as limited as possible in my dependence on other tech companies, but email just wasn't reasonable for me at all.