> PS: Some old firewalls block dynamic IPs for mail delivery. I'm not sure how common this is today, especially as SPAM and botnets have evolved a lot.
The problem is not that firewalls block dynamic IPs, but that a lot of mail servers, to deal with spam servers, started accepting mail only from some trusted smarthosts.
So there might be some server that will reject your mails. (I don't honestly know how much SPF makes things better.)
However, your ISP SMTP server will accept mail from its IP range (as they know how to find you if you abuse the service) and will relay mail for you. So probably your best bet is setup outgoing mail to go through it (Internet site with Smarthost, or something like that).
Ah, and don't forget to setup your server for SSL!
The problem is not that firewalls block dynamic IPs, but that a lot of mail servers, to deal with spam servers, started accepting mail only from some trusted smarthosts.
So there might be some server that will reject your mails. (I don't honestly know how much SPF makes things better.)
However, your ISP SMTP server will accept mail from its IP range (as they know how to find you if you abuse the service) and will relay mail for you. So probably your best bet is setup outgoing mail to go through it (Internet site with Smarthost, or something like that).
Ah, and don't forget to setup your server for SSL!