On 20/6/26 08:46, bput wrote:
I keep seeing general statements like this and as a postfix noob who is considering standing up a postfix server for incoming email and a separate one for outgoing mail (to prevent relay), I wonder if you can explain this further?
Josh's key word (and takeaway) was "deliverability". IP reputation is a thing that large (and potentially smaller) mail providers use. Additionally, there are lists out there which categorise your IP (including your static IP) as (e.g.) "ADSL residential" (my own static IP address was in this group for many years) that can be used to algorithmically determine if your "reputable" or not. You can jump through all the DKIM/SPF hoops to get your mail server "compliant" in the eyes of the current hegemon, and it still boils down to if they don't like the smell of your IP address on that day, your email will be categorised as spam, or not delivered (and if you're expecting a bounce, expect to be disappointed). Yahoo used to regularly block me on the account of "spam", yet every time I asked for proof they had none (only my mail server has outbound SMTP access). My last contract was with a large (now larger) South Australian University. Even they suffered at the hands of these current "RFC adjacent compliant" companies. I've run Unix mail servers (both professionally and personally) for years - it's not something I'd recommend for the faint of heart in current times. Note that I'm not dissuading you from it, but you may suffer scars. Cheers, --dt
