I don't know about other servers, but on the systems I manage gmail itself is the #1 spam source since 3 years at the very least. If you look at my previous posts, I commented on this two days ago.
There's literally _Zero_ value in DNSBL/DKIM/SPF because of this. Email sent from reputable sources is actually _more_ likely to be spam than small mail servers.
Content-based filters are the only thing that work against this sort of spam.
There's literally _Zero_ value in DNSBL/DKIM/SPF because of this. Email sent from reputable sources is actually _more_ likely to be spam than small mail servers.
Content-based filters are the only thing that work against this sort of spam.