On Thu, Jan 02, 2025 at 06:28:47PM +0800, jeremy ardley wrote:
I have been running my own inbound and outbound mail servers for over 30 years using ISP connections. The only time I ran into trouble was with gmail recently and only because of mismatched SPF records for a domain I host.
You're lucky, and your ISP is IMO atypical. Most ISP dialup (consumer/dynamic) IP ranges are identified and blocked by various anti-spam filters. Many ISPs also block outbound SMTP. My ISP does both, and provides (provided? I haven't tried it a decade) an outbound SMTP server which rewrote the Date: header (because why not), making it impossible to use DKIM at all. Static IPs can usually be "unlocked", but it's another hoop to jump through and static IPs often have a significant cost premium over dynamic IPs. Even if your ISP lets you use your IP for outbound SMTP, if it was previously used by a spammer you can forget it. For anyone just starting out I absolutely agree that running a mail server isn't worth the effort. For those of us who have been running one for decades, it at least provides a nice excuse to periodically complain about what the internet has become.
