Also have been running my own postfix mail server for several years now. It does take a bit of work to grok all the moving parts, but once you do it's actually quite straightforward.
As long as you have the following configured, then you shouldn't have any problems with getting classified as spam:
- Tight authorization on your SMTP server, obviously,
- SPF, to declare what IPs your domain sends from, so people can't spoof SMTP as you,
- DKIM to let your domain name sign your messages, so you can prove that you what arrived is what you intended to send,
- DMARC to link up the From header with the above, to prove that you're not spoofing senders, and
- The right MX and PTR records in youre DNS zones, to prove you're not spoofing IP addresses.
The above essentially amounts to setting up postfix, opendkim, and DNS, but there are a lot of moving parts, so it's easy to feel overwhelmed at first. Don't hesitate to PM me if you would like to set up your server and need some help.
As long as you have the following configured, then you shouldn't have any problems with getting classified as spam:
- Tight authorization on your SMTP server, obviously,
- SPF, to declare what IPs your domain sends from, so people can't spoof SMTP as you,
- DKIM to let your domain name sign your messages, so you can prove that you what arrived is what you intended to send,
- DMARC to link up the From header with the above, to prove that you're not spoofing senders, and
- The right MX and PTR records in youre DNS zones, to prove you're not spoofing IP addresses.
The above essentially amounts to setting up postfix, opendkim, and DNS, but there are a lot of moving parts, so it's easy to feel overwhelmed at first. Don't hesitate to PM me if you would like to set up your server and need some help.