LautreG

@[email protected]
Oh yes.
I can’t check, but I think there is setting to refuse connexion with the sender server if SPF doesn’t mach.
Like the policy in the DMARC?

Or, in spamd/spamassassin, to just drop the incoming email in these case?

(I’m on phone, I may write more wrongly than usual)

@[email protected]
There is 2 mechanisms against this.

• SPF
• Signature with DKIM
  Your provider should check these.
  Many providers don’t accept email if one is missing or wrong, or flag theses emails as spam.

@[email protected] @[email protected]
Some IP from DigitalOcean, or OVH make sometimes that the whole AS is considered suspicious.
I remember when I had a dedicated server at OVH, I needed many time to gain reputation. Also, may be the previous user for the IP trashed the reputation.
I also remember later, with a server at other place that I needed to ban the AS for several weeks to prevent flooding in log by trivial attacks.
Create good reputation need time. And, sometimes you need fill form (for Microsoft) with IP.