On 2/22/19 7:10 AM, Tim via users wrote:
If the numerical IP address of your service is shared between
yourselves and others, whether that's because your IP can change at
different logins, or other's use it simultaneously (such as webserver
hosts that service many clients on the same numerical IP), you're not
going to get the host to point their reverse DNS look-up to your domain
name. You need a permanently unique IP to be able to do that. The
same situation applies for HTTPS and certificates (you need to be the
sole user of your IP).
This hasn't been true for a long time. I don't remember the acronym,
but you can have an unlimited number of website hostnames on the same IP
address that all have their own unique certificates.
1. You need a mail server on an IP that the rest of the world is
willing to receive mail from. This will cost you more, and the average
consumer ISP might not be able to supply one to you.
The ISPs here in Canada block port 25 so you can't directly send out.
However, they provide a forwarder that you can send email through. You
probably can't setup of SPF or DKIM (I haven't tried), but I've never
had trouble sending mail from my server. I'm also not aware of anyone
not being able to send to me as well.