I have some domains registered that do not send mails.
I have totally removed MX record for these domains on my DNS.
Is it still useful to set an SPF record in order to avoid spammer to send mails as these domains?
I read here that for domains that do not send mail the SPF record setting is always:
mydomain.it. TXT "v=spf1 -all"
This is the simplest possible SPF record: it means your domain mydomain.it never sends mail.
But do I still need to set these since I even removed the MX record?
What I'm afraid is that some spammer uses one of these domains (domainA) and sends spam, since domainA is on the same IP of domainB that DO sends mail, I'm afraid an ISP could ban as spam mails coming from such IP and therefor mail coming also from domainB will be banned too.
FYI: I'm using a cPanel account with dedicated IP to host domains the mail server usese the same dedicated IP
UPDATE: from answers below I understood that for this specific case, SPF are not needed except for helping the interent in recognizing immediately as spam a spoofed email adreess using one of those domains. But none answerd to the last part of my question.
- Spammer sends mail pretending to be name@domainA.com
- domainA.com does not have MX record
- ISP recognizes name@domainA is spam, does the ISP ban the IP of domainA, or just the domainA???
- If ISP bans the IP of domainA, the poor domainB (with MX record) that DO sends email and it's on the same server IP would it get banned too, wouldn't it?