I have a forwarding domain (forwardingdomain.org > actual-website.org) for which I have email forwarders set up. To reduce spamming/spoofing of my email forwarders, I would like to set up a correct SPF TXT record in the domain’s DNS.
I have an SPF TXT record set up in the DNS, however, recently I’ve received scam/ransomware/spam emails that appear to be coming from email forwarders of the forwarding domain. So, that SPF record may not be working. I’ve successfully set up SPF TXT record for domains that have a website associated with them (i.e., I can use a server IP in the SPF record). For this domain, however, since it’s forwarding, it’s not clear what IP I should use.
Here’s the current SPF record (I don’t remember adding this myself; it may have gotten generated by itself):
Type: TXT Host: @ Value: v=spf1 a mx include:sendgrid.net ~all
Expected result: No more scam/spam/ransomware emails should be coming in that appear as if they were sent from my email forwarders.
Actual result: Scam/spam/ransomware emails are coming in, appearing to be sent from my email forwarders.